Method for patterning a coating on a surface and device including a patterned coating

ABSTRACT

An opto-electronic device includes: a first electrode; an organic layer disposed over the first electrode; a nucleation promoting coating disposed over the organic layer; a nucleation inhibiting coating covering a first region of the opto-electronic device; and a conductive coating covering a second region of the opto-electronic device.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.16/279,930 filed Feb. 19, 2019, which application is a continuation ofU.S. patent application Ser. No. 15/527,702, filed May 17, 2017, whichis a National Stage Entry of International Application No.PCT/IB2016/056442, filed Oct. 26, 2016, which claims the benefit of andpriority to U.S. Provisional Application No. 62/246,597, filed Oct. 26,2015, U.S. Provisional Application No. 62/277,989, filed Jan. 13, 2016,U.S. Provisional Application No. 62/373,927, filed Aug. 11, 2016, andU.S. Provisional Application No. 62/377,429, filed Aug. 19, 2016, thecontents of all such applications being incorporated herein by referencein their entireties.

TECHNICAL FIELD

The following generally relates to a method for depositing anelectrically conductive material on a surface. Specifically, the methodrelates to selective deposition of the electrically conductive materialon a surface for forming an electrically conductive structure of adevice.

BACKGROUND

Organic light emitting diodes (OLEDs) typically include several layersof organic materials interposed between conductive thin film electrodes,with at least one of the organic layers being an electroluminescentlayer. When a voltage is applied to electrodes, holes and electrons areinjected from an anode and a cathode, respectively. The holes andelectrons injected by the electrodes migrate through the organic layersto reach the electroluminescent layer. When a hole and an electron arein close proximity, they are attracted to each other due to a Coulombforce. The hole and electron may then combine to form a bound statereferred to as an exciton. An exciton may decay through a radiativerecombination process, in which a photon is released. Alternatively, anexciton may decay through a non-radiative recombination process, inwhich no photon is released. It is noted that, as used herein, internalquantum efficiency (IQE) will be understood to be a proportion of allelectron-hole pairs generated in a device which decay through aradiative recombination process.

A radiative recombination process can occur as a fluorescence orphosphorescence process, depending on a spin state of an electron-holepair (namely, an exciton). Specifically, the exciton formed by theelectron-hole pair may be characterized as having a singlet or tripletspin state. Generally, radiative decay of a singlet exciton results influorescence, whereas radiative decay of a triplet exciton results inphosphorescence.

More recently, other light emission mechanisms for OLEDs have beenproposed and investigated, including thermally activated delayedfluorescence (TADF). Briefly, TADF emission occurs through a conversionof triplet excitons into singlet excitons via a reverse inter systemcrossing process with the aid of thermal energy, followed by radiativedecay of the singlet excitons.

An external quantum efficiency (EQE) of an OLED device may refer to aratio of charge carriers provided to the OLED device relative to anumber of photons emitted by the device. For example, an EQE of 100%indicates that one photon is emitted for each electron that is injectedinto the device. As will be appreciated, an EQE of a device is generallysubstantially lower than an IQE of the device. The difference betweenthe EQE and the IQE can generally be attributed to a number of factorssuch as absorption and reflection of light caused by various componentsof the device.

An OLED device can typically be classified as being either a“bottom-emission” or “top-emission” device, depending on a relativedirection in which light is emitted from the device. In abottom-emission device, light generated as a result of a radiativerecombination process is emitted in a direction towards a base substrateof the device, whereas, in a top-emission device, light is emitted in adirection away from the base substrate. Accordingly, an electrode thatis proximal to the base substrate is generally made to be lighttransmissive (e.g., substantially transparent or semi-transparent) in abottom-emission device, whereas, in a top-emission device, an electrodethat is distal to the base substrate is generally made to be lighttransmissive in order to reduce attenuation of light. Depending on thespecific device structure, either an anode or a cathode may act as atransmissive electrode in top-emission and bottom-emission devices.

An OLED device also may be a double-sided emission device, which isconfigured to emit light in both directions relative to a basesubstrate. For example, a double-sided emission device may include atransmissive anode and a transmissive cathode, such that light from eachpixel is emitted in both directions. In another example, a double-sidedemission display device may include a first set of pixels configured toemit light in one direction, and a second set of pixels configured toemit light in the other direction, such that a single electrode fromeach pixel is transmissive.

In addition to the above device configurations, a transparent orsemi-transparent OLED device also can be implemented, in which thedevice includes a transparent portion which allows external light to betransmitted through the device. For example, in a transparent OLEDdisplay device, a transparent portion may be provided in a non-emissiveregion between each neighboring pixels. In another example, atransparent OLED lighting panel may be formed by providing a pluralityof transparent regions between emissive regions of the panel.Transparent or semi-transparent OLED devices may be bottom-emission,top-emission, or double-sided emission devices.

While either a cathode or an anode can be selected as a transmissiveelectrode, a typical top-emission device includes a light transmissivecathode. Materials which are typically used to form the transmissivecathode include transparent conducting oxides (TCOs), such as indium tinoxide (ITO) and zinc oxide (ZnO), as well as thin films, such as thoseformed by depositing a thin layer of silver (Ag), aluminum (Al), orvarious metallic alloys such as magnesium silver (Mg:Ag) alloy andytterbium silver (Yb:Ag) alloy with compositions ranging from about 1:9to about 9:1 by volume. A multi-layered cathode including two or morelayers of TCOs and/or thin metal films also can be used.

Particularly in the case of thin films, a relatively thin layerthickness of up to about a few tens of nanometers contributes toenhanced transparency and favorable optical properties (e.g., reducedmicrocavity effects) for use in OLEDs. However, a reduction in thethickness of a transmissive electrode is accompanied by an increase inits sheet resistance. An electrode with a high sheet resistance isgenerally undesirable for use in OLEDs, since it creates a largecurrent-resistance (IR) drop when a device is in use, which isdetrimental to the performance and efficiency of OLEDs. The IR drop canbe compensated to some extent by increasing a power supply level;however, when the power supply level is increased for one pixel,voltages supplied to other components are also increased to maintainproper operation of the device, and thus is unfavorable.

In order to reduce power supply specifications for top-emission OLEDdevices, solutions have been proposed to form busbar structures orauxiliary electrodes on the devices. For example, such an auxiliaryelectrode may be formed by depositing a conductive coating in electricalcommunication with a transmissive electrode of an OLED device. Such anauxiliary electrode may allow current to be carried more effectively tovarious regions of the device by lowering a sheet resistance and anassociated IR drop of the transmissive electrode.

Since an auxiliary electrode is typically provided on top of an OLEDstack including an anode, one or more organic layers, and a cathode,patterning of the auxiliary electrode is traditionally achieved using ashadow mask with mask apertures through which a conductive coating isselectively deposited, for example by a physical vapor deposition (PVD)process. However, since masks are typically metal masks, they have atendency to warp during a high-temperature deposition process, therebydistorting mask apertures and a resulting deposition pattern.Furthermore, a mask is typically degraded through successivedepositions, as a conductive coating adheres to the mask and obfuscatesfeatures of the mask. Consequently, such a mask should either be cleanedusing time-consuming and expensive processes or should be disposed oncethe mask is deemed to be ineffective at producing the desired pattern,thereby rendering such process highly costly and complex. Accordingly, ashadow mask process may not be commercially feasible for mass productionof OLED devices. Moreover, an aspect ratio of features which can beproduced using the shadow mask process is typically constrained due toshadowing effects and a mechanical (e.g., tensile) strength of the metalmask, since large metal masks are typically stretched during a shadowmask deposition process.

Another challenge of patterning a conductive coating onto a surfacethrough a shadow mask is that certain, but not all, patterns can beachieved using a single mask. As each portion of the mask is physicallysupported, not all patterns are possible in a single processing stage.For example, where a pattern specifies an isolated feature, a singlemask processing stage typically cannot be used to achieve the desiredpattern. In addition, masks which are used to produce repeatingstructures (e.g., busbar structures or auxiliary electrodes) spreadacross an entire device surface include a large number of perforationsor apertures formed on the masks. However, forming a large number ofapertures on a mask can compromise the structural integrity of the mask,thus leading to significant warping or deformation of the mask duringprocessing, which can distort a pattern of deposited structures.

SUMMARY

According to some embodiments, a device (e.g., an opto-electronicdevice) includes: (1) a first electrode; (2) an organic layer disposedover the first electrode; (3) a nucleation promoting coating disposedover the organic layer; (4) a nucleation inhibiting coating covering afirst region of the opto-electronic device; and (5) a conductive coatingcovering a second region of the opto-electronic device.

According to some embodiments, a device (e.g., an opto-electronicdevice) includes: (1) a substrate; (2) a nucleation inhibiting coatingcovering a first region of the substrate; and (3) a conductive coatingincluding a first portion and a second portion. The first portion of theconductive coating covers a second region of the substrate, the secondportion of the conductive coating partially overlaps the nucleationinhibiting coating, and the second portion of the conductive coating isspaced from the nucleation inhibiting coating by a gap.

According to some embodiments, a device (e.g., an opto-electronicdevice) includes: (1) a substrate including a first region and a secondregion; and (2) a conductive coating including a first portion and asecond portion. The first portion of the conductive coating covers thesecond region of the substrate, the second portion of the conductivecoating overlaps a portion of the first region of the substrate, and thesecond portion of the conductive coating is spaced from the first regionof the substrate by a gap.

According to some embodiments, a device (e.g., an opto-electronicdevice) includes: (1) a substrate; (2) a nucleation inhibiting coatingcovering a first region of the substrate; and (3) a conductive coatingcovering a laterally adjacent, second region of the substrate. Theconductive coating includes magnesium, and the nucleation inhibitingcoating is characterized as having an initial sticking probability formagnesium of no greater than about 0.02.

According to some embodiments, a manufacturing method of a device (e.g.,an opto-electronic device) includes: (1) providing a substrate and anucleation inhibiting coating covering a first region of the substrate;and (2) depositing a conductive coating covering a second region of thesubstrate. The conductive coating includes magnesium, and the nucleationinhibiting coating is characterized as having an initial stickingprobability for magnesium of no greater than 0.02.

BRIEF DESCRIPTION OF THE DRAWINGS

Some embodiments will now be described by way of example with referenceto the appended drawings wherein:

FIG. 1 is a schematic diagram illustrating a shadow mask deposition of anucleation inhibiting coating according to one embodiment;

FIG. 2A, FIG. 2B, and FIG. 2C are schematic diagrams illustrating amicro-contact transfer printing process of a nucleation inhibitingcoating according to one embodiment;

FIG. 3 is a schematic diagram illustrating the deposition of aconductive coating on a patterned surface according to one embodiment;

FIG. 4 is a diagram illustrating a device produced according to oneembodiment of a process;

FIGS. 5A-5C are schematic diagrams illustrating a process forselectively depositing a conductive coating according to one embodiment;

FIGS. 5D-5F are schematic diagrams illustrating a process forselectively depositing a conductive coating according to anotherembodiment;

FIG. 6 is a diagram illustrating an electroluminescent device accordingto one embodiment;

FIG. 7 is a flow diagram showing process stages according to oneembodiment;

FIG. 8 is a flow diagram showing process stages according to anotherembodiment;

FIG. 9A-9D are schematic diagrams illustrating the stages in theembodiment of FIG. 8;

FIG. 10 is a flow diagram showing process stages according to yetanother embodiment;

FIGS. 11A-11D are schematic diagrams illustrating the stages in theembodiment of FIG. 10;

FIG. 12 is a flow diagram showing process stages according to yetanother embodiment;

FIGS. 13A-13D are schematic diagrams illustrating the stages in theembodiment of FIG. 12;

FIG. 14 is a top view of an OLED device according to one embodiment;

FIG. 15 is a cross-sectional view of the OLED device of FIG. 14;

FIG. 16 is a cross-sectional view of an OLED device according to anotherembodiment;

FIG. 16B is a top view illustrating an open mask according to oneexample;

FIG. 16C is a top view illustrating an open mask according to anotherexample;

FIG. 16D is a top view illustrating an open mask according to yetanother example;

FIG. 16E is a top view illustrating an open mask according to yetanother example;

FIG. 17 is a top view illustrating a patterned electrode according toone embodiment;

FIG. 17B is a schematic diagram illustrating a top view of a passivematrix OLED device according to one embodiment;

FIG. 17C is a schematic cross-sectional view of the passive matrix OLEDdevice of FIG. 17B;

FIG. 17D is a schematic cross-sectional view of the passive matrix OLEDdevice of FIG. 17B after encapsulation;

FIG. 17E is a schematic cross-sectional view of a comparative passivematrix OLED device;

FIGS. 18A-18D illustrate portions of auxiliary electrodes according tovarious embodiments;

FIG. 19 illustrates a top view of a lead connected to an electrode of anOLED device according to one embodiment;

FIG. 20 illustrates a top view of a patterned electrode according to oneembodiment;

FIGS. 21A-21D illustrate patterned electrodes according to variousembodiments;

FIG. 22 illustrates repeating electrode units formed on an OLED deviceaccording to one embodiment;

FIG. 23 illustrates repeating electrode units formed on an OLED deviceaccording to another embodiment;

FIG. 24 illustrates repeating electrode units formed on an OLED deviceaccording to yet another embodiment;

FIGS. 25-28J illustrate auxiliary electrode patterns formed on OLEDdevices according to various embodiments;

FIG. 29 illustrate a portion of a device with a pixel arrangementaccording to one embodiment;

FIG. 30 is a cross-sectional diagram taken along line A-A of the deviceaccording to FIG. 29;

FIG. 31 is a cross-sectional diagram taken along line B-B of the deviceaccording to FIG. 29;

FIG. 32 is a diagram illustrating a portion of a device with a pixelarrangement according to another embodiment;

FIG. 33 is a micrograph of a device having the pixel arrangementillustrated in FIG. 32;

FIG. 34 is a diagram illustrating a cross-sectional profile around aninterface of a conductive coating and a nucleation inhibiting coatingaccording to one embodiment;

FIG. 35 is a diagram illustrating a cross-sectional profile around aninterface of a conductive coating and a nucleation inhibiting coatingaccording to another embodiment;

FIG. 36 is a diagram illustrating a cross-sectional profile around aninterface of a conductive coating, a nucleation inhibiting coating, anda nucleation promoting coating according to one embodiment;

FIG. 37 is a diagram illustrating a cross-sectional profile around aninterface of a conductive coating, a nucleation inhibiting coating, anda nucleation promoting coating according to another embodiment;

FIG. 38 is a diagram illustrating a cross-sectional profile around aninterface of a conductive coating and a nucleation inhibiting coatingaccording to yet another embodiment;

FIG. 39 is a diagram illustrating a cross-sectional profile of an activematrix OLED device according to one embodiment;

FIG. 40 is a diagram illustrating a cross-sectional profile of an activematrix OLED device according to another embodiment;

FIG. 41 is a diagram illustrating a cross-sectional profile of an activematrix OLED device according to yet another embodiment;

FIG. 42 is a diagram illustrating a cross-sectional profile of an activematrix OLED device according to yet another embodiment;

FIG. 43 is a diagram illustrating a transparent active matrix OLEDdevice according to one embodiment;

FIG. 44 is a diagram illustrating a cross-sectional profile of thedevice according to FIG. 43;

FIG. 45A is a SEM image of a top view of Sample 1;

FIGS. 45B and 45C are SEM images showing a magnified view of a portionof the sample of FIG. 45A;

FIG. 45D is a SEM image showing a cross-sectional view of the sample ofFIG. 45A;

FIG. 45E is a SEM image showing a cross-sectional view of the sample ofFIG. 45A;

FIG. 45F is a SEM image showing a cross-sectional view of anotherportion of the sample of FIG. 45A;

FIG. 45G is a tilted SEM image showing the sample portion of FIG. 45F;

FIG. 45H is a plot showing an EDX spectra taken from the sample of FIG.45A;

FIG. 46A is a SEM image of a top view of Sample 2;

FIG. 46B is a SEM image showing a magnified view of a portion of thesample of FIG. 46A;

FIG. 46C is a SEM image showing a further magnified view of the sampleportion of FIG. 46B;

FIG. 46D is a SEM image showing a cross-sectional view of the sample ofFIG. 46A;

FIGS. 46E and 46F are tilted SEM images showing a surface of the sampleof FIG. 46A;

FIG. 46G is a plot showing an EDX spectra taken from the sample of FIG.46A;

FIG. 46H shows a magnesium EDX spectrum overlaid on top of an SEM imageshowing a corresponding portion of the sample from which the spectrumwas obtained;

FIG. 47 is a schematic diagram illustrating a chamber set up forconducting deposition experiments using quartz crystal microbalances(QCMs);

FIG. 48 is a circuit diagram showing an example driving circuit for anactive matrix OLED display device;

FIG. 49 is a schematic illustration of a magnesium coating depositedbetween portions of a nucleation inhibiting coating;

FIG. 50A is a SEM image showing a top view of a sample fabricated usinga BAlq nucleation inhibiting coating;

FIG. 50B is a SEM image showing a magnified portion of the sample ofFIG. 50A;

FIGS. 50C and 50D are SEM images showing magnified portions of thesample of FIG. 50A;

FIG. 50E is a tilted SEM image showing a surface of the sample of FIG.50A;

FIG. 51A is a SEM image showing a top view of a comparative samplefabricated using a HT211 nucleation inhibiting coating;

FIG. 51B is a cross-sectional SEM image of the comparative sample ofFIG. 51A;

FIG. 52A is a SEM image showing a top view of a comparative samplefabricated using shadow mask deposition;

FIG. 52B is a cross-sectional SEM image of the comparative sample ofFIG. 52A;

FIG. 53 is a plot of transmittance versus wavelength for comparativesamples fabricated with HT211 nucleation inhibiting coatings depositedat various deposition rates;

FIG. 54 is a plot of transmittance versus wavelength for samplesfabricated with various nucleation inhibiting coatings;

FIG. 55 is a top view showing a pattern of an auxiliary electrodeaccording to one example embodiment;

FIG. 56 is a plot showing sheet resistance specifications and associatedauxiliary electrode thicknesses for various display panel sizes;

FIG. 57 is a plot showing a layer thickness of magnesium deposited on areference QCM surface versus a layer thickness of magnesium deposited ona sample QCM surface covered with various nucleation modifying coatings;

FIG. 58 is a plot showing a sticking probability of magnesium vapor on asample QCM surface versus a layer thickness of magnesium deposited onthe sample QCM surface covered with various nucleation modifyingcoatings; and

FIGS. 59A and 59B illustrate a process for removing a nucleationinhibiting coating following deposition of a conductive coatingaccording to one embodiment.

DETAILED DESCRIPTION

It will be appreciated that for simplicity and clarity of illustration,where considered appropriate, reference numerals may be repeated amongthe figures to indicate corresponding or analogous components. Inaddition, numerous specific details are set forth in order to provide athorough understanding of example embodiments described herein. However,it will be understood by those of ordinary skill in the art that theexample embodiments described herein may be practiced without some ofthose specific details. In other instances, certain methods, proceduresand components have not been described in detail so as not to obscurethe example embodiments described herein.

In one aspect according to some embodiments, a method for depositing anelectrically conductive coating on a surface is provided. In someembodiments, the method is performed in the context of a manufacturingmethod of an opto-electronic device. In some embodiments, the method isperformed in the context of a manufacturing method of another device. Insome embodiments, the method includes depositing a nucleation inhibitingcoating on a first region of a substrate to produce a patternedsubstrate. The patterned substrate includes the first region covered bythe nucleation inhibiting coating, and a second region of the substratethat is exposed from, or is substantially free of or is substantiallyuncovered by, the nucleation inhibiting coating. The method alsoincludes treating the patterned substrate to deposit the conductivecoating on the second region of the substrate. In some embodiments, amaterial of the conductive coating includes magnesium. In someembodiments, treating the patterned substrate includes treating both thenucleation inhibiting coating and the second region of the substrate todeposit the conductive coating on the second region of the substrate,while the nucleation inhibiting coating remains exposed from, or issubstantially free of or is substantially uncovered by, the conductivecoating. In some embodiments, treating the patterned substrate includesperforming evaporation or sublimation of a source material used to formthe conductive coating, and exposing both the nucleation inhibitingcoating and the second region of the substrate to the evaporated sourcematerial.

As used herein, the term “nucleation inhibiting” is used to refer to acoating or a layer of a material having a surface which exhibits arelatively low affinity towards deposition of an electrically conductivematerial, such that the deposition of the conductive material on thesurface is inhibited, while the term “nucleation promoting” is used torefer to a coating or a layer of a material having a surface whichexhibits a relatively high affinity towards deposition of anelectrically conductive material, such that the deposition of theconductive material on the surface is facilitated. One measure ofnucleation inhibiting or nucleation promoting property of a surface isan initial sticking probability of the surface for an electricallyconductive material, such as magnesium. For example, a nucleationinhibiting coating with respect to magnesium can refer to a coatinghaving a surface which exhibits a relatively low initial stickingprobability for magnesium vapor, such that deposition of magnesium onthe surface is inhibited, while a nucleation promoting coating withrespect to magnesium can refer to a coating having a surface whichexhibits a relatively high initial sticking probability for magnesiumvapor, such that deposition of magnesium on the surface is facilitated.As used herein, the terms “sticking probability” and “stickingcoefficient” may be used interchangeably. Another measure of nucleationinhibiting or nucleation promoting property of a surface is an initialdeposition rate of an electrically conductive material, such asmagnesium, on the surface relative to an initial deposition rate of theconductive material on another (reference) surface, where both surfacesare subjected or exposed to an evaporation flux of the conductivematerial.

As used herein, the terms “evaporation” and “sublimation” areinterchangeably used to generally refer to deposition processes in whicha source material is converted into a vapor (e.g., by heating) to bedeposited onto a target surface in, for example, a solid state.

As used herein, a surface (or a certain area of the surface) which is“substantially free of” or “is substantially uncovered by” a materialrefers to a substantial absence of the material on the surface (or thecertain area of the surface). Specifically regarding an electricallyconductive coating, one measure of an amount of an electricallyconductive material on a surface is a light transmittance, sinceelectrically conductive materials, such as metals including magnesium,attenuate and/or absorb light. Accordingly, a surface can be deemed tobe substantially free of an electrically conductive material if thelight transmittance is greater than 90%, greater than 92%, greater than95%, or greater than 98% in the visible portion of the electromagneticspectrum. Another measure of an amount of a material on a surface is apercentage coverage of the surface by the material, such as where thesurface can be deemed to be substantially free of the material if thepercentage coverage by the material is no greater than 10%, no greaterthan 8%, no greater than 5%, no greater than 3%, or no greater than 1%.Surface coverage can be assessed using imaging techniques, such as usingtransmission electron microscopy, atomic force microscopy, or scanningelectron microscopy.

FIG. 1 is a schematic diagram illustrating a process of depositing anucleation inhibiting coating 140 onto a surface 102 of a substrate 100according to one embodiment. In the embodiment of FIG. 1, a source 120including a source material is heated under vacuum to evaporate orsublime the source material. The source material includes orsubstantially consists of a material used to form the nucleationinhibiting coating 140. The evaporated source material then travels in adirection indicated by arrow 122 towards the substrate 100. A shadowmask 110 having an aperture or slit 112 is disposed in the path of theevaporated source material such that a portion of a flux travellingthrough the aperture 112 is selectively incident on a region of thesurface 102 of the substrate 100, thereby forming the nucleationinhibiting coating 140 thereon.

FIGS. 2A-2C illustrate a micro-contact transfer printing process fordepositing a nucleation inhibiting coating on a surface of a substratein one embodiment. Similarly to a shadow mask process, the micro-contactprinting process may be used to selectively deposit the nucleationinhibiting coating on a region of a substrate surface.

FIG. 2A illustrates a first stage of the micro-contact transfer printingprocess, wherein a stamp 210 including a protrusion 212 is provided witha nucleation inhibiting coating 240 on a surface of the protrusion 212.As will be understood by persons skilled in the art, the nucleationinhibiting coating 240 may be deposited on the surface of the protrusion212 using various suitable processes.

As illustrated in FIG. 2B, the stamp 210 is then brought into proximityof a substrate 100, such that the nucleation inhibiting coating 240deposited on the surface of the protrusion 212 is in contact with asurface 102 of the substrate 100. Upon the nucleation inhibiting coating240 contacting the surface 102, the nucleation inhibiting coating 240adheres to the surface 102 of the substrate 100.

As such, when the stamp 210 is moved away from the substrate 100 asillustrated in FIG. 2C, the nucleation inhibiting coating 240 iseffectively transferred onto the surface 102 of the substrate 100.

Once a nucleation inhibiting coating has been deposited on a region of asurface of a substrate, a conductive coating may be deposited onremaining uncovered region(s) of the surface where the nucleationinhibiting coating is not present. Turning to FIG. 3, a conductivecoating source 410 is illustrated as directing an evaporated conductivematerial towards a surface 102 of a substrate 100. As illustrated inFIG. 3, the conducting coating source 410 may direct the evaporatedconductive material such that it is incident on both covered or treatedareas (namely, region(s) of the surface 102 with the nucleationinhibiting coating 140 deposited thereon) and uncovered or untreatedareas of the surface 102. However, since a surface of the nucleationinhibiting coating 140 exhibits a relatively low initial stickingcoefficient compared to that of the uncovered surface 102 of thesubstrate 100, a conductive coating 440 selectively deposits onto theareas of the surface 102 where the nucleation inhibiting coating 140 isnot present. For example, an initial deposition rate of the evaporatedconductive material on the uncovered areas of the surface 102 may be atleast or greater than about 80 times, at least or greater than about 100times, at least or greater than about 200 times, at least or greaterthan about 500 times, at least or greater than about 700 times, at leastor greater than about 1000 times, at least or greater than about 1500times, at least or greater than about 1700 times, or at least or greaterthan about 2000 times an initial deposition rate of the evaporatedconductive material on the surface of the nucleation inhibiting coating140. The conductive coating 440 may include, for example, pure orsubstantially pure magnesium.

It will be appreciated that although shadow mask patterning andmicro-contact transfer printing processes have been illustrated anddescribed above, other processes may be used for selectively patterninga substrate by depositing a nucleation inhibiting material. Variousadditive and subtractive processes of patterning a surface may be usedto selectively deposit a nucleation inhibiting coating. Examples of suchprocesses include, but are not limited to, photolithography, printing(including ink or vapor jet printing and reel-to-reel printing), organicvapor phase deposition (OVPD), and laser induced thermal imaging (LITI)patterning, and combinations thereof.

In some applications, it may be desirable to deposit a conductivecoating having specific material properties onto a substrate surface onwhich the conductive coating cannot be readily deposited. For example,pure or substantially pure magnesium typically cannot be readilydeposited onto an organic surface due to low sticking coefficients ofmagnesium on various organic surfaces. Accordingly, in some embodiments,the substrate surface is further treated by depositing a nucleationpromoting coating thereon prior to depositing the conductive coating,such as one including magnesium.

Based on findings and experimental observations, it is postulated thatfullerenes and other nucleation promoting materials, as will beexplained further herein, act as nucleation sites for the deposition ofa conductive coating including magnesium. For example, in cases wheremagnesium is deposited using an evaporation process on a fullerenetreated surface, the fullerene molecules act as nucleation sites thatpromote formation of stable nuclei for magnesium deposition. Less than amonolayer of fullerene or other nucleation promoting material may beprovided on the treated surface to act as nucleation sites fordeposition of magnesium in some cases. As will be understood, treatingthe surface by depositing several monolayers of a nucleation promotingmaterial may result in a higher number of nucleation sites, and thus ahigher initial sticking probability.

It will also be appreciated that an amount of fullerene or othermaterial deposited on a surface may be more, or less, than onemonolayer. For example, the surface may be treated by depositing 0.1monolayer, 1 monolayer, 10 monolayers, or more of a nucleation promotingmaterial or a nucleation inhibiting material. As used herein, depositing1 monolayer of a material refers to an amount of the material to cover adesired area of a surface with a single layer of constituent moleculesor atoms of the material. Similarly, as used herein, depositing 0.1monolayer of a material refers to an amount of the material to cover 10%of a desired area of a surface with a single layer of constituentmolecules or atoms of the material. Due to, for example, possiblestacking or clustering of molecules or atoms, an actual thickness of adeposited material may be non-uniform. For example, depositing 1monolayer of a material may result in some regions of a surface beinguncovered by the material, while other regions of the surface may havemultiple atomic or molecular layers deposited thereon.

As used herein, the term “fullerene” refers to a material includingcarbon molecules. Examples of fullerene molecules include carbon cagemolecules including a three-dimensional skeleton that includes multiplecarbon atoms, which form a closed shell, and which can be spherical orsemi-spherical in shape. A fullerene molecule can be designated asC_(n), where n is an integer corresponding to a number of carbon atomsincluded in a carbon skeleton of the fullerene molecule. Examples offullerene molecules include C_(n), where n is in the range of 50 to 250,such as C₆₀, C₇₀, C₇₂, C₇₄, C₇₆, C₇₈, C₈₀, C₈₂, and C₈₄. Additionalexamples of fullerene molecules include carbon molecules in a tube orcylindrical shape, such as single-walled carbon nanotubes andmulti-walled carbon nanotubes.

FIG. 4 illustrates an embodiment of a device in which a nucleationpromoting coating 160 is deposited prior to the deposition of aconductive coating 440. As illustrated in FIG. 4, the nucleationpromoting coating 160 is deposited over regions of the substrate 100that are uncovered by a nucleation inhibiting coating 140. Accordingly,when the conductive coating 440 is deposited, the conductive coating 440forms preferentially over the nucleation promoting coating 160. Forexample, an initial deposition rate of a material of the conductivecoating 440 on a surface of the nucleation promoting coating 160 may beat least or greater than about 80 times, at least or greater than about100 times, at least or greater than about 200 times, at least or greaterthan about 500 times, at least or greater than about 700 times, at leastor greater than about 1000 times, at least or greater than about 1500times, at least or greater than about 1700 times, or at least or greaterthan about 2000 times an initial deposition rate of the material on asurface of the nucleation inhibiting coating 140. In general, thenucleation promoting coating 160 may be deposited on the substrate 100prior to, or following, the deposition of the nucleation inhibitingcoating 140. Various processes for selectively depositing a material ona surface may be used to deposit the nucleation promoting coating 160including, but not limited to, evaporation (including thermalevaporation and electron beam evaporation), photolithography, printing(including ink or vapor jet printing, reel-to-reel printing, andmicro-contact transfer printing), OVPD, LITI patterning, andcombinations thereof.

FIGS. 5A-5C illustrate a process for depositing a conductive coatingonto a surface of a substrate in one embodiment.

In FIG. 5A, a surface 102 of a substrate 100 is treated by depositing anucleation inhibiting coating 140 thereon. Specifically, in theillustrated embodiment, deposition is achieved by evaporating a sourcematerial inside a source 120, and directing the evaporated sourcematerial towards the surface 102 to be deposited thereon. The generaldirection in which the evaporated flux is directed towards the surface102 is indicated by arrow 122. As illustrated, deposition of thenucleation inhibiting coating 140 may be performed using an open mask orwithout a mask, such that the nucleation inhibiting coating 140substantially covers the entire surface 102 to produce a treated surface142. Alternatively, the nucleation inhibiting coating 140 may beselectively deposited onto a region of the surface 102 using, forexample, a selective deposition technique described above.

While the nucleation inhibiting coating 140 is illustrated as beingdeposited by evaporation, it will be appreciated that other depositionand surface coating techniques may be used, including but not limited tospin coating, dip coating, printing, spray coating, OVPD, LITIpatterning, physical vapor deposition (PVD) (including sputtering),chemical vapor deposition (CVD), and combinations thereof.

In FIG. 5B, a shadow mask 110 is used to selectively deposit anucleation promoting coating 160 on the treated surface 142. Asillustrated, an evaporated source material travelling from the source120 is directed towards the substrate 100 through the mask 110. The maskincludes an aperture or slit 112 such that a portion of the evaporatedsource material incident on the mask 110 is prevented from travelingpast the mask 110, and another portion of the evaporated source materialdirected through the aperture 112 of the mask 110 selectively depositsonto the treated surface 142 to form the nucleation promoting coating160. Accordingly, a patterned surface 144 is produced upon completingthe deposition of the nucleation promoting coating 160.

FIG. 5C illustrates a stage of depositing a conductive coating 440 ontothe patterned surface 144. The conductive coating 440 may include, forexample, pure or substantially pure magnesium. As will be explainedfurther below, a material of the conductive coating 440 exhibits arelatively low initial sticking coefficient with respect to thenucleation inhibiting coating 140 and a relatively high initial stickingcoefficient with respect to the nucleation promoting coating 160.Accordingly, the deposition may be performed using an open mask orwithout a mask to selectively deposit the conductive coating 440 ontoregions of the substrate 100 where the nucleation promoting coating 160is present. As illustrated in FIG. 5C, an evaporated material of theconductive coating 440 that is incident on a surface of the nucleationinhibiting coating 140 may be largely or substantially prevented frombeing deposited onto the nucleation inhibiting coating 140.

FIGS. 5D-5F illustrate a process for depositing a conductive coatingonto a surface of a substrate in another embodiment.

In FIG. 5D, a nucleation promoting coating 160 is deposited on a surface102 of a substrate 100. For example, the nucleation promoting coating160 may be deposited by thermal evaporation using an open mask orwithout a mask. Alternatively, other deposition and surface coatingtechniques may be used, including but not limited to spin coating, dipcoating, printing, spray coating, OVPD, LITI patterning, PVD (includingsputtering), CVD, and combinations thereof.

In FIG. 5E, a nucleation inhibiting coating 140 is selectively depositedover a region of the nucleation promoting coating 160 using a shadowmask 110. Accordingly, a patterned surface is produced upon completingthe deposition of the nucleation inhibiting coating 140. Then in FIG.5F, a conductive coating 440 is deposited onto the patterned surfaceusing an open mask or a mask-free deposition process, such that theconductive coating 440 is formed over exposed regions of the nucleationpromoting coating 160.

In the foregoing embodiments, it will be appreciated that the conductivecoating 440 formed by the processes may be used as an electrode or aconductive structure for an electronic device. For example, theconductive coating 440 may be an anode or a cathode of an organicopto-electronic device, such as an OLED device or an organicphotovoltaic (OPV) device. In addition, the conductive coating 440 mayalso be used as an electrode for opto-electronic devices includingquantum dots as an active layer material. For example, such a device mayinclude an active layer disposed between a pair of electrodes with theactive layer including quantum dots. The device may be, for example, anelectroluminescent quantum dot display device in which light is emittedfrom the quantum dot active layer as a result of current provided by theelectrodes. The conductive coating 440 may also be a busbar or anauxiliary electrode for any of the foregoing devices.

Accordingly, it will be appreciated that the substrate 100 onto whichvarious coatings are deposited may include one or more additionalorganic and/or inorganic layers not specifically illustrated ordescribed in the foregoing embodiments. For example, in the case of anOLED device, the substrate 100 may include one or more electrodes (e.g.,an anode and/or a cathode), charge injection and/or transport layers,and an electroluminescent layer. The substrate 100 may further includeone or more transistors and other electronic components such asresistors and capacitors, which are included in an active-matrix or apassive-matrix OLED device. For example, the substrate 100 may includeone or more top-gate thin-film transistors (TFTs), one or morebottom-gate TFTs, and/or other TFT structures. A TFT may be an n-typeTFT or a p-type TFT. Examples of TFT structures include those includingamorphous silicon (a-Si), indium gallium zinc oxide (IGZO), andlow-temperature polycrystalline silicon (LTPS).

The substrate 100 may also include a base substrate for supporting theabove-identified additional organic and/or inorganic layers. Forexample, the base substrate may be a flexible or rigid substrate. Thebase substrate may include, for example, silicon, glass, metal, polymer(e.g., polyimide), sapphire, or other materials suitable for use as thebase substrate.

The surface 102 of the substrate 100 may be an organic surface or aninorganic surface. For example, if the conductive coating 440 is for useas a cathode of an OLED device, the surface 102 may be a top surface ofa stack of organic layers (e.g., a surface of an electron injectionlayer). In another example, if the conductive coating 440 is for use asan auxiliary electrode of a top-emission OLED device, the surface 102may be a top surface of an electrode (e.g., a common cathode).Alternatively, such an auxiliary electrode may be formed directlybeneath a transmissive electrode on top of a stack of organic layers.

FIG. 6 illustrates an electroluminescent (EL) device 600 according toone embodiment. The EL device 600 may be, for example, an OLED device oran electroluminescent quantum dot device. In one embodiment, the device600 is an OLED device including a base substrate 616, an anode 614,organic layers 630, and a cathode 602. In the illustrated embodiment,the organic layers 630 include a hole injection layer 612, a holetransport layer 610, an electroluminescent layer 608, an electrontransport layer 606, and an electron injection layer 604.

The hole injection layer 612 may be formed using a hole injectionmaterial which generally facilitates the injection of holes by the anode614. The hole transport layer 610 may be formed using a hole transportmaterial, which is generally a material that exhibits high holemobility.

The electroluminescent layer 608 may be formed, for example, by doping ahost material with an emitter material. The emitter material may be afluorescent emitter, a phosphorescent emitter, or a TADF emitter, forexample. A plurality of emitter materials may also be doped into thehost material to form the electroluminescent layer 608.

The electron transport layer 606 may be formed using an electrontransport material which generally exhibits high electron mobility. Theelectron injection layer 604 may be formed using an electron injectionmaterial, which generally acts to facilitate the injection of electronsby the cathode 602.

It will be understood that the structure of the device 600 may be variedby omitting or combining one or more layers. Specifically, one or moreof the hole injection layer 612, the hole transport layer 610, theelectron transport layer 606, and the electron injection layer 604 maybe omitted from the device structure. One or more additional layers mayalso be present in the device structure. Such additional layers include,for example, a hole blocking layer, an electron blocking layer, andadditional charge transport and/or injection layers. Each layer mayfurther include any number of sub-layers, and each layer and/orsub-layer may include various mixtures and composition gradients. Itwill also be appreciated that the device 600 may include one or morelayers containing inorganic and/or organo-metallic materials, and is notlimited to devices composed solely of organic materials. For example,the device 600 may include quantum dots.

The device 600 may be connected to a power source 620 for supplyingcurrent to the device 600.

In another embodiment where the device 600 is an EL quantum dot device,the EL layer 608 generally includes quantum dots, which emit light whencurrent is supplied.

FIG. 7 is a flow diagram outlining stages of fabricating an OLED deviceaccording to one embodiment. In 704, organic layers are deposited on atarget surface. For example, the target surface may be a surface of ananode that has been deposited on top of a base substrate, which mayinclude, for example, glass, polymer, and/or metal foil. As discussedabove, the organic layers may include, for example, a hole injectionlayer, a hole transport layer, an electroluminescence layer, an electrontransport layer, and an electron injection layer. A nucleationinhibiting coating is then deposited on top of the organic layers instage 706 using a selective deposition or patterning process. In stage708, a nucleation promoting coating is selectively deposited on thenucleation inhibiting coating to produce a patterned surface. Forexample, the nucleation promoting coating and the nucleation inhibitingcoating may be selectively deposited by evaporation using a mask,micro-contact transfer printing process, photolithography, printing(including ink or vapor jet printing and reel-to-reel printing), OVPD,or LITI patterning. A conductive coating is then deposited on thepatterned surface using an open mask or a mask-free deposition processin stage 710. The conductive coating may serve as a cathode or anotherconductive structure of the OLED device.

Referring next to FIGS. 8 and 9A-9D, a process for fabricating an OLEDdevice according to another embodiment is provided. FIG. 8 is a flowdiagram outlining stages for fabricating the OLED device, and FIGS.9A-9D are schematic diagrams illustrating the device at each stage ofthe process. In stage 804, organic layers 920 are deposited on a targetsurface 912 using a source 991. In the illustrated embodiment, thetarget surface 912 is a surface of an anode 910 that has been depositedon top of a base substrate 900. The organic layers 920 may include, forexample, a hole injection layer, a hole transport layer, anelectroluminescence layer, an electron transport layer, and an electroninjection layer. A nucleation promoting coating 930 is then deposited ontop of the organic layers 920 in stage 806 using a source 993 and anopen mask, or without a mask. In stage 808, a nucleation inhibitingcoating 940 is selectively deposited on the nucleation promoting coating930 using a mask 980 and a source 995, thereby producing a patternedsurface. A conductive coating 950 is then deposited on the patternedsurface using an open mask or a mask-free deposition process in stage810, such that the conductive coating 950 is deposited on regions of thenucleation promoting coating 930 which are not covered by the nucleationinhibiting coating 940.

Referring next to FIGS. 10 and 11A-11D, a process for fabricating anOLED device according to yet another embodiment is provided. FIG. 10 isa flow diagram outlining stages for fabricating the OLED device, andFIGS. 11A-11D are schematic diagrams illustrating the stages of such aprocess. In stage 1004, organic layers 1120 are deposited on a targetsurface 1112 using a source 1191. In the illustrated embodiment, thetarget surface 1112 is a surface of an anode 1110 that has beendeposited on top of a base substrate 1100. The organic layers 1120 mayinclude, for example, a hole injection layer, a hole transport layer, anelectroluminescence layer, an electron transport layer, and an electroninjection layer. A nucleation inhibiting coating 1130 is then depositedon top of the organic layers 1120 in stage 1006 using a mask 1180 and asource 1193, such that the nucleation inhibiting coating 1130 isselectively deposited on a region of a surface of the organic layers1120 that is exposed through an aperture of the mask 1180. In stage1008, a nucleation promoting coating 1140 is selectively deposited usinga mask 1182 and a source 1195. In the illustrated embodiment, thenucleation promoting coating 1140 is shown as being deposited overregions of the surface of the organic layers 1120 which are not coveredby the nucleation inhibiting coating 1130, thereby producing a patternedsurface. A conductive coating 1150 is then deposited on the patternedsurface using an open mask or a mask-free deposition process in stage1010, resulting in the conductive coating 1150 being deposited on asurface of the nucleation promoting coating 1140 while leaving a surfaceof the nucleation inhibiting coating 1130 substantially free of amaterial of the conductive coating 1150.

Referring next to FIGS. 12 and 13A-13D, a process for fabricating anOLED device according to yet another embodiment is provided. FIG. 12 isa flow diagram outlining stages for fabricating the OLED device, andFIGS. 13A-13D are schematic diagrams illustrating the stages of such aprocess. In stage 1204, organic layers 1320 are deposited on a targetsurface 1312 using a source 1391. In the illustrated embodiment, thetarget surface 1312 is a surface of an anode 1310 that has beendeposited on top of a base substrate 1300. The organic layers 1320 mayinclude, for example, a hole injection layer, a hole transport layer, anelectroluminescence layer, an electron transport layer, and an electroninjection layer. A nucleation promoting coating 1330 is then depositedon top of the organic layers 1320 in stage 1206 using a mask 1380 and asource 1393, such that the nucleation promoting coating 1330 isselectively deposited on a region of a surface of the organic layers1320 that is exposed through an aperture of the mask 1380. In stage1208, a nucleation inhibiting layer 1340 is selectively deposited usinga mask 1382 and a source 1395. In the illustrated embodiment, thenucleation inhibiting coating 1340 is illustrated as being depositedover regions of the surface of the organic layers 1320 which are notcovered by the nucleation promoting coating 1330, thereby producing apatterned surface. A conductive coating 1350 is then deposited on thepatterned surface using an open mask or a mask-free deposition processin stage 1210, resulting in the conductive coating 1350 being depositedon a surface of the nucleation promoting coating 1330 while leaving asurface of the nucleation inhibiting coating 1340 substantially free ofa material of the conductive coating 1350. The conductive coating 1350formed in this manner may serve as an electrode (e.g., a cathode).

In accordance with the above-described embodiments, a conductive coatingmay be selectively deposited on target regions (e.g., non-emissiveregions) using an open mask or a mask-free deposition process, throughthe use of a nucleation inhibiting coating or a combination ofnucleation inhibiting and nucleation promoting coatings. By contrast,the lack of sufficient selectivity in an open mask or a mask-freedeposition process would result in deposition of a conductive materialbeyond target regions and over emissive regions, which is undesiredsince the presence of such material over the emissive regions generallycontributes to attenuation of light and thus a decrease in an EQE of anOLED device. Moreover, by providing high selectivity in depositing aconductive coating on target regions, the conductive coating can serveas an electrode with a sufficient thickness to achieve a desiredconductivity in an OLED device. For example, the high selectivityprovided by the above-described embodiments allows deposition of anauxiliary electrode having a high aspect ratio that remains confined toregions between neighbouring pixels or sub-pixels. By contrast, the lackof sufficient selectivity in forming a thick electrode in an open maskor a mask-free deposition process would result in deposition of a thickcoating of a conductive material over both emissive and non-emissiveregions, thus substantially decreasing a performance of a resulting OLEDdevice.

For the sake of simplicity and clarity, details of deposited materialsincluding thickness profiles and edge profiles have been omitted fromthe process diagrams.

The formation of thin films during vapor deposition on a surface of asubstrate involves processes of nucleation and growth. During initialstages of film formation, a sufficient number of vapor monomers (e.g.,atoms or molecules) typically condense from a vapor phase to forminitial nuclei on the surface. As vapor monomers continue to impingeupon the surface, a size and density of these initial nuclei increase toform small clusters or islands. After reaching a saturation islanddensity, adjacent islands typically will start to coalesce, increasingan average island size, while decreasing an island density. Coalescenceof adjacent islands continues until a substantially closed film isformed.

There can be three basic growth modes for the formation of thinfilms: 1) island (Volmer-Weber), 2) layer-by-layer (Frank-van derMerwe), and 3) Stranski-Krastanov. Island growth typically occurs whenstable clusters of monomers nucleate on a surface and grow to formdiscrete islands. This growth mode occurs when the interactions betweenthe monomers is stronger than that between the monomers and the surface.

The nucleation rate describes how many nuclei of a critical size form ona surface per unit time. During initial stages of film formation, it isunlikely that nuclei will grow from direct impingement of monomers onthe surface, since the density of nuclei is low, and thus the nucleicover a relatively small fraction of the surface (e.g., there are largegaps/spaces between neighboring nuclei). Therefore, the rate at whichcritical nuclei grow typically depends on the rate at which adsorbedmonomers (e.g., adatoms) on the surface migrate and attach to nearbynuclei.

After adsorption of an adatom on a surface, the adatom may either desorbfrom the surface, or may migrate some distance on the surface beforeeither desorbing, interacting with other adatoms to form a smallcluster, or attach to a growing nuclei. An average amount of time thatan adatom remains on the surface after initial adsorption is given by:

$\tau_{s} = {\frac{1}{v}{\exp \left( \frac{E_{des}}{kT} \right)}}$

In the above equation, visa vibrational frequency of the adatom on thesurface, k is the Boltzmann constant, T is temperature, and E_(des) isan energy involved to desorb the adatom from the surface. From thisequation it is noted that the lower the value of E_(des) the easier itis for the adatom to desorb from the surface, and hence the shorter thetime the adatom will remain on the surface. A mean distance an adatomcan diffuse is given by,

$X = {a_{0}{\exp \left( \frac{E_{des} - E_{S}}{2{kT}} \right)}}$

where a₀ is a lattice constant and E_(S) is an activation energy forsurface diffusion. For low values of E_(des) and/or high values of E_(S)the adatom will diffuse a shorter distance before desorbing, and henceis less likely to attach to a growing nuclei or interact with anotheradatom or cluster of adatoms.

During initial stages of film formation, adsorbed adatoms may interactto form clusters, with a critical concentration of clusters per unitarea being given by,

$\frac{N_{i}}{n_{0}} = {{\frac{N_{1}}{n_{0}}}^{i}\mspace{14mu} {\exp \left( \frac{E_{i}}{kT} \right)}}$

where E_(i) is an energy involved to dissociate a critical clustercontaining i adatoms into separate adatoms, n₀ is a total density ofadsorption sites, and N₁ is a monomer density given by:

N₁={dot over (R)}τ_(s)

where {dot over (R)} is a vapor impingement rate. Typically i willdepend on a crystal structure of a material being deposited and willdetermine the critical cluster size to form a stable nucleus.

A critical monomer supply rate for growing clusters is given by the rateof vapor impingement and an average area over which an adatom candiffuse before desorbing:

${\overset{.}{R}X^{2}} = {a_{0}^{2}{\exp \left( \frac{E_{des} - E_{S}}{kT} \right)}}$

The critical nucleation rate is thus given by the combination of theabove equations:

${\overset{.}{N}}_{i} = {\overset{.}{R}a_{0}^{2}{n_{0}\left( \frac{\overset{.}{R}}{{vn}_{0}} \right)}^{i}\mspace{14mu} {\exp \left( \frac{{\left( {i + 1} \right)E_{des}} - E_{S} + E_{i}}{kT} \right)}}$

From the above equation it is noted that the critical nucleation ratewill be suppressed for surfaces that have a low desorption energy foradsorbed adatoms, a high activation energy for diffusion of an adatom,are at high temperatures, or are subjected to low vapor impingementrates.

Sites of substrate heterogeneities, such as defects, ledges or stepedges, may increase E_(des), leading to a higher density of nucleiobserved at such sites. Also, impurities or contamination on a surfacemay also increase E_(des), leading to a higher density of nuclei. Forvapor deposition processes conducted under high vacuum conditions, thetype and density of contaminates on a surface is affected by a vacuumpressure and a composition of residual gases that make up that pressure.

Under high vacuum conditions, a flux of molecules that impinge on asurface (per cm²-sec) is given by:

$\Phi = {3.513 \times 10^{22}\frac{P}{MT}}$

where P is pressure, and M is molecular weight. Therefore, a higherpartial pressure of a reactive gas, such as H₂O, can lead to a higherdensity of contamination on a surface during vapor deposition, leadingto an increase in E_(des) and hence a higher density of nuclei.

A useful parameter for characterizing nucleation and growth of thinfilms is the sticking probability given by:

$S = \frac{N_{ads}}{N_{total}}$

where N_(ads) is a number of adsorbed monomers that remain on a surface(e.g., are incorporated into a film) and N_(total) is a total number ofimpinging monomers on the surface. A sticking probability equal to 1indicates that all monomers that impinge the surface are adsorbed andsubsequently incorporated into a growing film. A sticking probabilityequal to 0 indicates that all monomers that impinge the surface aredesorbed and subsequently no film is formed on the surface. A stickingprobability of metals on various surfaces can be evaluated using varioustechniques of measuring the sticking probability, such as a dual quartzcrystal microbalance (QCM) technique as described by Walker et al., J.Phys. Chem. C 2007, 111, 765 (2006) and in the Examples section below.

As the density of islands increases (e.g., increasing average filmthickness), a sticking probability may change. For example, a lowinitial sticking probability may increase with increasing average filmthickness. This can be understood based on a difference in stickingprobability between an area of a surface with no islands (baresubstrate) and an area with a high density of islands. For example, amonomer that impinges a surface of an island may have a stickingprobability close to 1.

An initial sticking probability S₀ can therefore be specified as asticking probability of a surface prior to the formation of anysignificant number of critical nuclei. One measure of an initialsticking probability can involve a sticking probability of a surface fora material during an initial stage of deposition of the material, wherean average thickness of the deposited material across the surface is ator below threshold value. In the description of some embodiments, athreshold value for an initial sticking probability can be specified as1 nm. An average sticking probability is then given by:

S=S ₀(1−A _(nuc))+S _(nuc)(A _(nuc))

where S_(nuc) is a sticking probability of an area covered by islands,and A_(nuc) is a percentage of an area of a substrate surface covered byislands.

Suitable materials for use to form a nucleation inhibiting coatinginclude those exhibiting or characterized as having an initial stickingprobability for a material of a conductive coating of no greater than orless than about 0.1 (or 10%) or no greater than or less than about 0.05,and, more particularly, no greater than or less than about 0.03, nogreater than or less than about 0.02, no greater than or less than about0.01, no greater than or less than about 0.08, no greater than or lessthan about 0.005, no greater than or less than about 0.003, no greaterthan or less than about 0.001, no greater than or less than about0.0008, no greater than or less than about 0.0005, or no greater than orless than about 0.0001. Suitable materials for use to form a nucleationpromoting coating include those exhibiting or characterized as having aninitial sticking probability for a material of a conductive coating ofat least about 0.6 (or 60%), at least about 0.7, at least about 0.75, atleast about 0.8, at least about 0.9, at least about 0.93, at least about0.95, at least about 0.98, or at least about 0.99.

Suitable nucleation inhibiting materials include organic materials, suchas small molecule organic materials and organic polymers. Examples ofsuitable organic materials include polycyclic aromatic compoundsincluding organic molecules which may optionally include one or moreheteroatoms, such as nitrogen (N), sulfur (S), oxygen (O), phosphorus(P), and aluminum (Al). In some embodiments, a polycyclic aromaticcompound includes organic molecules each including a core moiety and atleast one terminal moiety bonded to the core moiety. A number ofterminal moieties may be 1 or more, 2 or more, 3 or more, or 4 or more.In the case of 2 or more terminal moieties, the terminal moieties may bethe same or different, or a subset of the terminal moieties may be thesame but different from at least one remaining terminal moiety. In someembodiments, at least one terminal moiety is, or includes, a biphenylylmoiety represented by one of the chemical structures (I-a), (I-b), and(Ic) as follows:

wherein the dotted line indicates a bond formed between the biphenylylmoiety and the core moiety. In general, the biphenylyl moietyrepresented by (I-a), (I-b) and (I-c) may be unsubstituted or may besubstituted by having one or more of its hydrogen atoms replaced by oneor more substituent groups. In the moiety represented by (I-a), (I-b),and (I-c), R_(a) and R_(b) independently represent the optional presenceof one or more substituent groups, wherein R_(a) may represent mono, di,tri, or tetra substitution, and Rb may represent mono, di, tri, tetra,or penta substitution. For example, one or more substituent groups,R_(a) and R_(b), may independently be selected from: deutero, fluoro,alkyl including C₁-C₄ alkyl, cycloalkyl, arylalkyl, silyl, aryl,heteroaryl, fluoroalkyl, and any combinations thereof. Particularly, oneor more substituent groups, R_(a) and R_(b), may be independentlyselected from: methyl, ethyl, t-butyl, trifluoromethyl, phenyl,methylphenyl, dimethylphenyl, trimethylphenyl, t-butylphenyl,biphenylyl, methylbiphenylyl, dimethylbiphenylyl, trimethylbiphenylyl,t-butylbiphenylyl, fluorophenyl, difluorophenyl, trifluorophenyl,polyfluorophenyl, fluorobiphenylyl, difluorobiphenylyl,trifluorobiphenylyl, and polyfluorobiphenylyl. Without wishing to bebound by a particular theory, the presence of an exposed biphenylylmoiety on a surface may serve to adjust or tune a surface energy (e.g.,a desorption energy) to lower an affinity of the surface towardsdeposition of a conductive material such as magnesium. Other moietiesand materials that yield a similar tuning of a surface energy to inhibitdeposition of magnesium may be used to form a nucleation inhibitingcoating.

In another embodiment, at least one terminal moiety is, or includes, aphenyl moiety represented by the structure (I-d) as follows:

wherein the dotted line indicates a bond formed between the phenylmoiety and the core moiety. In general, the phenyl moiety represented by(I-d) may be unsubstituted or may be substituted by having one or moreof its hydrogen atoms replaced by one or more substituent groups. In themoiety represented by (I-d), R_(c) represents the optional presence ofone or more substituent groups, wherein R_(c) may represent mono, di,tri, tetra, or penta substitution. One or more substituent groups,R_(c), may be independently selected from: deutero, fluoro, alkylincluding C₁-C₄ alkyl, cycloalkyl, silyl, fluoroalkyl, and anycombinations thereof. Particularly, one or more substituent groups,R_(c), may be independently selected from: methyl, ethyl, t-butyl,fluoromethyl, bifluoromethyl, trifluoromethyl, fluoroethyl, andpolyfluoroethyl.

In yet another embodiment, at least one terminal moiety is, or includes,a polycyclic aromatic moiety including fused ring structures, such asfluorene moieties or phenylene moieties (including those containingmultiple (e.g., 3, 4, or more) fused benzene rings). Examples of suchmoieties include spirobifluorene moiety, triphenylene moiety,diphenylfluorene moiety, dimethylfluorene moiety, difluorofluorenemoiety, and any combinations thereof.

In some embodiments, a polycyclic aromatic compound includes organicmolecules represented by at least one of chemical structures (II),(III), and (IV) as follows:

In (II), (III), and (IV), C represents a core moiety, and T₁, T₂, and T₃represent terminal moieties bonded to the core moiety. Although 1, 2,and 3 terminal moieties are depicted in (II), (III), and (IV), it shouldbe understood that more than 3 terminal moieties also may be included.

In some embodiments, C is, or includes, a heterocyclic moiety, such as aheterocyclic moiety including one or more nitrogen atoms, for which anexample is a triazole moiety. In some embodiments, C is, or includes, ametal atom (including transition and post-transition atoms), such as analuminum atom, a copper atom, an iridium atom, and/or a platinum atom.In some embodiments, C is, or includes, a nitrogen atom, an oxygen atom,and/or a phosphorus atom. In some embodiments, C is, or includes, acyclic hydrocarbon moiety, which may be aromatic. In some embodiments, Cis, or includes, a substituted or unsubstituted alkyl, which may bebranched or unbranched, a cycloalkynyl (including those containingbetween 1 and 7 carbon atoms), an alkenyl, an alkynyl, an aryl(including phenyl, naphthyl, thienyl, and indolyl), an arylalkyl, aheterocyclic moiety (including cyclic amines such as morpholino,piperdino and pyrolidino), a cyclic ether moiety (such astetrahydrofuran and tetrahydropyran moieties), a heteroaryl (includingpyrrole, furan, thiophene, imidazole, oxazole, thiazole, triazole,pyrazole, pyridine, pyrazine, pyrimidine, polycyclic heteroaromaticmoieties, and dibenzylthiophenyl), fluorene moieties, silyl, and anycombinations thereof.

In (II), (III), and (IV), T₁ is, or includes, a moiety represented by(I-a), (I-b), (I-c), or (I-d), or a polycyclic aromatic moiety includingfused ring structures as described above. The moiety, T₁, may bedirectly bonded to the core moiety, or may be bonded to the core moietyvia a linker moiety. Examples of a linker moiety include —O— (where Odenotes an oxygen atom), —S— (where S denotes a sulfur atom), and cyclicor acyclic hydrocarbon moieties including 1, 2, 3, 4, or more carbonatoms, and which may be unsubstituted or substituted, and which mayoptionally include one or more heteroatoms. The bond between the coremoiety and one or more terminal moieties may be a covalent bond or abond formed between a metallic element and an organic element,particularly in the case of organometallic compounds.

In (III), T₁ and T₂ may be the same or different, as long as at least T₁is, or includes, a moiety represented by (I-a), (I-b), (I-c), or (I-d),or a polycyclic aromatic moiety including fused ring structures asdescribed above. For example, each of T₁ and T₂ may be, or may include,a moiety represented by (I-a), (I-b), (I-c), or (I-d), or a polycyclicaromatic moiety including fused ring structures as described above. Asanother example, T₁ is, or includes, a moiety represented by (I-a),(I-b), (I-c), or (I-d), or a polycyclic aromatic moiety including fusedring structures as described above, while T₂ may lack such a moiety. Insome embodiments, T₂ is, or includes, a cyclic hydrocarbon moiety, whichmay be aromatic, which may include a single ring structure or may bepolycyclic, which may be substituted or unsubstituted, and which may bedirectly bonded to the core moiety, or may be bonded to the core moietyvia a linker moiety. In some embodiments, T₂ is, or includes, aheterocyclic moiety, such as a heterocyclic moiety including one or morenitrogen atoms, which may include a single ring structure or may bepolycyclic, which may be substituted or unsubstituted, and which may bedirectly bonded to the core moiety, or may be bonded to the core moietyvia a linker moiety. In some embodiments, T₂ is, or includes, an acyclichydrocarbon moiety, which may be unsubstituted or substituted, which mayoptionally include one or more heteroatoms, and which may be directlybonded to the core moiety, or may be bonded to the core moiety via alinker moiety. In some embodiments where T₁ and T₂ are different, T₂ maybe selected from moieties having sizes comparable to T₁. Specifically,T₂ may be selected from the above-listed moieties having molecularweights no greater than about 2 times, no greater than about 1.9 times,no greater than about 1.7 times, no greater than about 1.5 times, nogreater than about 1.2 times, or no greater than about 1.1 times amolecular weight of T₁. Without wishing to be bound by a particulartheory, it is postulated that, when the terminal moiety T₂ is includedwhich is different from or lacks a moiety represented by (I-a), (I-b),(I-c), or (I-d), or a polycyclic aromatic moiety including fused ringstructures as described above, a comparable size of T₂ with respect toT₁ may promote exposure of T₁ on a surface, in contrast to bulkyterminal groups that may hinder exposure of T₁ due to molecularstacking, steric hindrance, or a combination of such effects.

In (IV), T₁, T₂, and T₃ may be the same or different, as long as atleast T₁ is, or includes, a moiety represented by (I-a), (I-b), (I-c),or (I-d), or a polycyclic aromatic moiety including fused ringstructures as described above. For example, each of T₁, T₂, and T₃ maybe, or may include, a moiety represented by (I-a), (I-b), (I-c), or(I-d), or a polycyclic aromatic moiety including fused ring structuresas described above. As another example, each of T₁ and T₂ may be, or mayinclude, a moiety represented by (I-a), (I-b), (I-c), or (I-d), or apolycyclic aromatic moiety including fused ring structures as describedabove, while T₃ may lack such a moiety. As another example, each of T₁and T₃ may be, or may include, a moiety represented by (I-a), (I-b),(I-c), or (I-d), or a polycyclic aromatic moiety including fused ringstructures as described above, while T₂ may lack such a moiety. As afurther example, T₁ is, or includes, a moiety represented by (I-a),(I-b), (I-c), or (I-d), or a polycyclic aromatic moiety including fusedring structures as described above, while both T₂ and T₃ may lack such amoiety. In some embodiments, at least one T₂ and T₃ is, or includes, acyclic hydrocarbon moiety, which may be aromatic, which may include asingle ring structure or may be polycyclic, which may be substituted orunsubstituted, and which may be directly bonded to the core moiety, ormay be bonded to the core moiety via a linker moiety. In someembodiments, at least one T₂ and T₃ is, or includes, a heterocyclicmoiety, such as a heterocyclic moiety including one or more nitrogenatoms, which may include a single ring structure or may be polycyclic,which may be substituted or unsubstituted, and which may be directlybonded to the core moiety, or may be bonded to the core moiety via alinker moiety. In some embodiments, at least one T₂ and T₃ is, orincludes, an acyclic hydrocarbon moiety, which may be unsubstituted orsubstituted, which may optionally include one or more heteroatoms, andwhich may be directly bonded to the core moiety, or may be bonded to thecore moiety via a linker moiety. In some embodiments where T₁, T₂, andT₃ are different, T₂ and T₃ may be selected from moieties having sizescomparable to T₁. Specifically, T₂ and T₃ may be selected from theabove-listed moieties having molecular weights no greater than about 2times, no greater than about 1.9 times, no greater than about 1.7 times,no greater than about 1.5 times, no greater than about 1.2 times, or nogreater than about 1.1 times a molecular weight of Ti. Without wishingto be bound by a particular theory, it is postulated that, when theterminal moieties T₂ and T₃ are included which are different from orlacks a moiety represented by (I-a), (I-b), (I-c), or (I-d), or apolycyclic aromatic moiety including fused ring structures as describedabove, a comparable size of T₂ and T₃ with respect to T₁ may promoteexposure of T₁ on a surface, in contrast to bulky terminal groups thatmay hinder exposure of T₁ due to molecular stacking, steric hindrance,or a combination of such effects.

Suitable nucleation inhibiting materials include polymeric materials.Examples of such polymeric materials include: fluoropolymers, includingbut not limited to perfluorinated polymers and polytetrafluoroethylene(PTFE); polyvinylbiphenyl; polyvinylcarbazole (PVK); and polymers formedby polymerizing a plurality of the polycyclic aromatic compounds asdescribed above. In another example, polymeric materials includepolymers formed by polymerizing a plurality of monomers, wherein atleast one of the monomers includes a terminal moiety that is, orincludes, a moiety represented by (I-a), (I-b), (I-c), or (I-d), or apolycyclic aromatic moiety including fused ring structures as describedabove.

FIGS. 14 and 15 illustrates an OLED device 1500 according to oneembodiment. Specifically, FIG. 14 shows a top view of the OLED device1500, and FIG. 15 illustrates a cross-sectional view of a structure ofthe OLED device 1500. In FIG. 14, a cathode 1550 is illustrated as asingle monolithic or continuous structure having or defining a pluralityof apertures or holes 1560 formed therein, which correspond to regionsof the device 1500 where a cathode material was not deposited. This isfurther illustrated in FIG. 15, which shows the OLED device 1500including a base substrate 1510, an anode 1520, organic layers 1530, anucleation promoting coating 1540, a nucleation inhibiting coating 1570selectively deposited over certain regions of the nucleation promotingcoating 1540, and the cathode 1550 deposited over other regions of thenucleation promoting coating 1540 where the nucleation inhibitingcoating 1570 is not present. More specifically, by selectivelydepositing the nucleation inhibiting coating 1570 to cover certainregions of a surface of the nucleation promoting coating 1540 during thefabrication of the device 1500, the cathode material is selectivelydeposited on exposed regions of the surface of the nucleation promotingcoating 1540 using an open mask or a mask-free deposition process. Thetransparency or transmittance of the OLED device 1500 may be adjusted ormodified by changing various parameters of an imparted pattern, such asan average size of the holes 1560 and a density of the holes 1560 formedin the cathode 1550. Accordingly, the OLED device 1500 may be asubstantially transparent OLED device, which allows at least a portionof an external light incident on the OLED device to be transmittedtherethrough. For example, the OLED device 1500 may be a substantiallytransparent OLED lighting panel. Such OLED lighting panel may be, forexample, configured to emit light in one direction (e.g., either towardsor away from the base substrate 1510) or in both directions (e.g.,towards and away from the base substrate 1510).

FIG. 16 illustrates an OLED device 1600 according to another embodimentin which a cathode 1650 substantially covers an entire device area.Specifically, the OLED device 1600 includes a base substrate 1610, ananode 1620, organic layers 1630, a nucleation promoting coating 1640,the cathode 1650, a nucleation inhibiting coating 1660 selectivelydeposited over certain regions of the cathode 1650, and an auxiliaryelectrode 1670 deposited over other regions of the cathode 1650 wherethe nucleation inhibiting coating 1660 is not present.

The auxiliary electrode 1670 is electrically connected to the cathode1650. Particularly in a top-emission configuration, it is desirable todeposit a relatively thin layer of the cathode 1650 to reduce opticalinterference (e.g., attenuation, reflection, diffusion, and so forth)due to the presence of the cathode 1650. However, a reduced thickness ofthe cathode 1650 generally increases a sheet resistance of the cathode1650, thus reducing the performance and efficiency of the OLED device1600. By providing the auxiliary electrode 1670 that is electricallyconnected to the cathode 1650, the sheet resistance and thus the IR dropassociated with the cathode 1650 can be decreased. Furthermore, byselectively depositing the auxiliary electrode 1670 to cover certainregions of the device area while other regions remain uncovered, opticalinterference due to the presence of the auxiliary electrode 1670 may becontrolled and/or reduced.

The effect of an electrode sheet resistance will now be explained withreference to FIG. 48, which shows an example of a circuit diagram for atop-emission active matrix OLED (AMOLED) pixel with a p-type TFT. InFIG, 48, a circuit 4800 includes a power supply (VDD) line 4812, acontrol line 4814, a gate line 4816, and a data line 4818. A drivingcircuit including a first TFT 4831, a second TFT 4833, and a storagecapacitor 4841 is provided, and the driving circuit components areconnected to the data line 4818, the gate line 4816, and the VDD line4812 in the manner illustrated in the figure. A compensation circuit4843 is also provided, which generally acts to compensate for anydeviation in transistor properties caused by manufacturing variances ordegradation of the TFTs 4831 and 4833 over time.

An OLED pixel or subpixel 4850 and a cathode 4852, which is representedas a resistor in the circuit diagram, are connected in series with thesecond TFT 4833 (also referred to as a “driving transistor”). Thedriving transistor 4833 regulates a current passed through the OLEDpixel 4850 in accordance with a voltage of a charge stored in thestorage capacitor 4841, such that the OLED pixel 4850 outputs a desiredluminance. The voltage of the storage capacitor 4841 is set byconnecting the storage capacitor 4841 to the data line 4818 via thefirst TFT 4831 (also referred to as a “switch transistor”).

Since the current through the OLED pixel or subpixel 4850 and thecathode 4852 is regulated based on a potential difference between a gatevoltage and a source voltage of the driving transistor 4833, an increasein a sheet resistance of the cathode 4852 results in a greater IR drop,which is compensated by increasing the power supply (VDD). However, whenthe VDD is increased, other voltages supplied to the TFT 4833 and theOLED pixel 4850 are also increased to maintain proper operation, andthus is unfavorable.

Referring to FIG. 48, an auxiliary electrode 4854 is illustrated as aresistor connected in parallel to the cathode 4852. Since the resistanceof the auxiliary electrode 4854 is substantially lower than that of thecathode 4852, a combined effective resistance of the auxiliary electrode4854 and the cathode 4852 is lower than that of the cathode 4852 alone.Accordingly, an increase in the VDD can be mitigated by the presence ofthe auxiliary electrode 4854.

While the advantages of auxiliary electrodes have been explained inreference to top-emission OLED devices, it may also be advantageous toselectively deposit an auxiliary electrode over a cathode of abottom-emission or double-sided emission OLED device. For example, whilethe cathode may be formed as a relatively thick layer in abottom-emission OLED device without substantially affecting opticalcharacteristics of the device, it may still be advantageous to form arelatively thin cathode. For example, in a transparent orsemi-transparent display device, layers of the entire device including acathode can be formed to be substantially transparent orsemi-transparent. Accordingly, it may be beneficial to provide apatterned auxiliary electrode which cannot be readily detected by anaked eye from a typical viewing distance. It will also be appreciatedthat the described processes may be used to form busbars or auxiliaryelectrodes for decreasing a resistance of electrodes for devices otherthan OLED devices.

In some embodiments, a nucleation inhibiting coating deposited during afabrication process may be removed by using, for example, a solvent orplasma etching after a conductive coating has been deposited.

FIG. 59A illustrates a device 5901 according to one embodiment, whichincludes a substrate 5910 and a nucleation inhibiting coating 5920 and aconductive coating 5915 (e.g., a magnesium coating) deposited overrespective regions of a surface of the substrate 5910.

FIG. 59B illustrates a device 5902 after the nucleation inhibitingcoating 5920 present in the device 5901 has been removed from thesurface of the substrate 5910, such that the conductive coating 5915remains on the substrate 5910 and regions of the substrate 5910 whichwere covered by the nucleation inhibiting coating 5920 are now exposedor uncovered. For example, the nucleation inhibiting coating 5920 of thedevice 5901 may be removed by exposing the substrate 5910 to solvent orplasma which preferentially reacts and/or etches away the nucleationinhibiting coating 5920 without substantially affecting the conductivecoating 5915.

At least some of the above embodiments have been described in referenceto various layers or coatings, including a nucleation promoting coating,a nucleation inhibiting coating, and a conductive coating, being formedusing an evaporation process. As will be understood, an evaporationprocess is a type of PVD process where one or more source materials areevaporated or sublimed under a low pressure (e.g., vacuum) environmentand deposited on a target surface through de-sublimation of the one ormore evaporated source materials. A variety of different evaporationsources may be used for heating a source material, and, as such, it willbe appreciated that the source material may be heated in various ways.For example, the source material may be heated by an electric filament,electron beam, inductive heating, or by resistive heating. In addition,such layers or coatings may be deposited and/or patterned using othersuitable processes, including photolithography, printing, OVPD, LITIpatterning, and combinations thereof. These processes may also be usedin combination with a shadow mask to achieve various patterns.

For example, magnesium may be deposited at source temperatures up toabout 600° C. to achieve a faster rate of deposition, such as about 10to 30 nm per second or more. Referring to Table 1 below, variousdeposition rates measured using a Knudsen cell source to depositsubstantially pure magnesium on a fullerene-treated organic surface ofabout 1 nm are provided. It will be appreciated that other factors mayalso affect a deposition rate including, but not limited to, a distancebetween a source and a substrate, characteristics of the substrate,presence of a nucleation promoting coating on the substrate, the type ofsource used and a shaping of a flux of material evaporated from thesource.

TABLE 1 Magnesium Deposition Rate by Temperature Sample # Temperature (°C.) Rate (angstroms/s) 1 510 10 2 525 40 3 575 140 4 600 160

It will be appreciated by those skilled in the art that particularprocessing conditions used may vary depending on an equipment being usedto conduct a deposition. It will also be appreciated that higherdeposition rates are generally attained at higher source temperatures;however, other deposition conditions can be selected, such as, forexample, by placing a substrate closer to a deposition source.

It will also be appreciated that an open mask used for deposition of anyof various layers or coatings, including a conductive coating, anucleation inhibiting coating, and a nucleation promoting coating, may“mask” or prevent deposition of a material on certain regions of asubstrate. However, unlike a fine metal mask (FMM) used to formrelatively small features with a feature size on the order of tens ofmicrons or smaller, a feature size of an open mask is generallycomparable to the size of an OLED device being manufactured. Forexample, the open mask may mask edges of a display device duringmanufacturing, which would result in the open mask having an aperturethat approximately corresponds to a size of the display device (e.g.about 1 inch for micro-displays, about 4-6 inches for mobile displays,about 8-17 inches for laptop or tablet displays, and so forth). Forexample, the feature size of an open mask may be on the order of about 1cm or greater.

FIG. 16B illustrates an example of an open mask 1731 having or definingan aperture 1734 formed therein. In the illustrated example, theaperture 1734 of the mask 1731 is smaller than a size of a device 1721,such that, when the mask 1731 is overlaid, the mask 1731 covers edges ofthe device 1721. Specifically, in the illustrated embodiments, all orsubstantially all emissive regions or pixels 1723 of the device 1721 areexposed through the aperture 1734, while an unexposed region 1727 isformed between outer edges 1725 of the device 1721 and the aperture1734. As would be appreciated, electrical contacts or other devicecomponents may be located in the unexposed region 1727 such that thesecomponents remain unaffected through the open mask deposition process.

FIG. 16C illustrates another example of an open mask 1731 where anaperture 1734 of the mask 1731 is smaller than that of FIG. 16B, suchthat the mask 1731 covers at least some emissive regions or pixels 1723of a device 1721 when overlaid. Specifically, outer-most pixels 1723′are illustrated as being located within an unexposed region 1727 of thedevice 1721 formed between the aperture 1734 of the mask 1731 and outeredges 1725 of the device 1721.

FIG. 16D illustrates yet another example of an open mask 1731 wherein anaperture 1734 of the mask 1731 defines a pattern, which covers somepixels 1723′ while exposing other pixels 1723 of a device 1721.Specifically, the pixels 1723′ located within an unexposed region 1727of the device 1721 (formed between the aperture 1734 and outer edges1725) are masked during the deposition process to inhibit a vapor fluxfrom being incident on the unexposed region 1727.

While outer-most pixels have been illustrated as being masked in theexamples of FIGS. 16B-16D, it will be appreciated that an aperture of anopen mask may be shaped to mask other emissive and non-emissive regionsof a device. Furthermore, while an open mask has been illustrated in theforegoing examples as having one aperture, the open mask may alsoinclude additional apertures for exposing multiple regions of asubstrate or a device.

FIG. 16E illustrates another example of an open mask 1731, where themask 1731 has or defines a plurality of apertures 1734 a-1734 d. Theapertures 1734 a-1734 d are positioned such that they selectively exposecertain regions of a device 1721 while masking other regions. Forexample, certain emissive regions or pixels 1723 are exposed through theapertures 1734 a-d, while other pixels 1723′ located within an unexposedregion 1727 are masked.

In various embodiments described herein, it will be understood that theuse of an open mask may be omitted, if desired. Specifically, an openmask deposition process described herein may alternatively be conductedwithout the use of a mask, such that an entire target surface isexposed.

Although certain processes have been described with reference toevaporation for purposes of depositing a nucleation promoting material,a nucleation inhibiting material, and magnesium, it will be appreciatedthat various other processes may be used to deposit these materials. Forexample, deposition may be conducted using other PVD processes(including sputtering), CVD processes (including plasma enhancedchemical vapor deposition (PECVD)), or other suitable processes fordepositing such materials. In some embodiments, magnesium is depositedby heating a magnesium source material using a resistive heater. Inother embodiments, a magnesium source material may be loaded in a heatedcrucible, a heated boat, a Knudsen cell (e.g., an effusion evaporatorsource), or any other type of evaporation source.

A deposition source material used to deposit a conductive coating may bea mixture or a compound, and, in some embodiments, at least onecomponent of the mixture or compound is not deposited on a substrateduring deposition (or is deposited in a relatively small amount comparedto, for example, magnesium). In some embodiments, the source materialmay be a copper-magnesium (Cu—Mg) mixture or a Cu—Mg compound. In someembodiments, the source material for a magnesium deposition sourceincludes magnesium and a material with a lower vapor pressure thanmagnesium, such as, for example, Cu. In other embodiments, the sourcematerial for a magnesium deposition source is substantially puremagnesium. Specifically, substantially pure magnesium can exhibitsubstantially similar properties (e.g., initial sticking probabilitieson nucleation inhibiting and promoting coatings) compared to puremagnesium (99.99% and higher purity magnesium). For example, an initialsticking probability of substantially pure magnesium on a nucleationinhibiting coating can be within ±10% or within ±5% of an initialsticking probability of 99.99% purity magnesium on the nucleationinhibiting coating. Purity of magnesium may be about 95% or higher,about 98% or higher, about 99% or higher, or about 99.9% or higher.Deposition source materials used to deposit a conductive coating mayinclude other metals in place of, or in combination with, magnesium. Forexample, a source material may include high vapor pressure materials,such as ytterbium (Yb), cadmium (Cd), zinc (Zn), or any combinationthereof.

Furthermore, it will be appreciated that the processes of variousembodiments may be performed on surfaces of other various organic orinorganic materials used as an electron injection layer, an electrontransport layer, an electroluminescent layer, and/or a pixel definitionlayer (PDL) of an organic opto-electronic device. Examples of suchmaterials include organic molecules as well as organic polymers such asthose described in PCT Publication No. WO 2012/016074. It will also beunderstood by persons skilled in the art that organic materials dopedwith various elements and/or inorganic compounds may still be consideredto be an organic material. It will further be appreciated by thoseskilled in the art that various organic materials may be used, and theprocesses described herein are generally applicable to an entire rangeof such organic materials.

It will also be appreciated that an inorganic substrate or surface canrefer to a substrate or surface primarily including an inorganicmaterial. For greater clarity, an inorganic material will generally beunderstood to be any material that is not considered to be an organicmaterial. Examples of inorganic materials include metals, glasses, andminerals. Specifically, a conductive coating including magnesium may bedeposited using a process according to the present disclosure onsurfaces of lithium fluoride (LiF), glass and silicon (Si). Othersurfaces on which the processes according to the present disclosure maybe applied include those of silicon or silicone-based polymers,inorganic semiconductor materials, electron injection materials, salts,metals, and metal oxides.

It will be appreciated that a substrate may include a semiconductormaterial, and, accordingly, a surface of such a substrate may be asemiconductor surface. A semiconductor material may be described as amaterial which generally exhibits a band gap. For example, such a bandgap may be formed between a highest occupied molecular orbital (HOMO)and a lowest unoccupied molecular orbital (LUMO). Semiconductormaterials thus generally possess electrical conductivity that is lessthan that of a conductive material (e.g., a metal) but greater than thatof an insulating material (e.g., a glass). It will be understood that asemiconductor material may be an organic semiconductor material or aninorganic semiconductor material.

FIG. 17 shows a patterned cathode 1710 according to one embodiment. Thecathode 1710 is illustrated as a single monolithic or continuousstructure including a plurality of substantially straight conductorsegments, which are spaced apart and arranged substantially parallelwith respect to one another. Each conductor segment is connected at bothof its ends to end conductor segments, which are arranged substantiallyperpendicular to the plurality of substantially straight conductorsegments. The cathode 1710 can be formed in accordance with thedeposition processes described above.

FIG. 17B shows a patterned cathode 1712 according to another embodiment,in which the cathode 1712 includes a plurality of spaced apart andelongated conductive strips. For example, the cathode 1712 may be usedin a passive matrix OLED device (PMOLED) 1715. In the PMOLED device1715, emissive regions or pixels are generally formed at regions wherecounter-electrodes overlap. Accordingly, in the embodiment of FIG. 17B,emissive regions or pixels 1751 are formed at overlapping regions of thecathode 1712 and an anode 1741, which includes a plurality of spacedapart and elongated conductive strips. Non-emissive regions 1755 areformed at regions where the cathode 1712 and the anode 1741 do notoverlap. Generally, the strips of the cathode 1712 and the strips of theanode 1741 are oriented substantially perpendicular to each other in thePMOLED device 1715 as illustrated. The cathode 1712 and the anode 1741may be connected to a power source and associated driving circuitry forsupplying current to the respective electrodes.

FIG. 17C illustrates a cross-sectional view taken along line A-A in FIG.17B. In FIG. 17C, a base substrate 1702 is provided, which may be, forexample, a transparent substrate. The anode 1741 is provided over thebase substrate 1702 in the form of strips as illustrated in FIG. 17B.One or more organic layers 1761 are deposited over the anode 1741. Forexample, the organic layers 1761 may be provided as a common layeracross the entire device, and may include any number of layers oforganic and/or inorganic materials described herein, such as holeinjection and transport layers, an electroluminescence layer, andelectron transport and injection layers. Certain regions of a topsurface of the organic layers 1761 are illustrated as being covered by anucleation inhibition coating 1771, which is used to selectively patternthe cathode 1712 in accordance with the deposition processes describedabove. The cathode 1712 and the anode 1741 may be connected to theirrespective drive circuitry (not shown), which controls emission of lightfrom the pixels 1751.

While thicknesses of the nucleation inhibiting coating 1771 and thecathode 1712 may be varied depending on the desired application andperformance, at least in some embodiments, the thickness of thenucleation inhibiting coating 1771 may be comparable to, orsubstantially less than, the thickness of the cathode 1712 asillustrated in FIG. 17C. The use of a relatively thin nucleationinhibiting coating to achieve patterning of a cathode may beparticularly advantageous for flexible PMOLED devices, since it canprovide a relatively planar surface onto which a barrier coating may beapplied.

FIG. 17D illustrates the PMOLED device 1715 of FIG. 17C with a barriercoating 1775 applied over the cathode 1712 and the nucleation inhibitingcoating 1771. As will be appreciated, the barrier coating 1775 isgenerally provided to inhibit the various device layers, includingorganic layers and the cathode 1712 which may be prone to oxidation,from being exposed to moisture and ambient air. For example, the barriercoating 1775 may be a thin film encapsulation formed by printing, CVD,sputtering, atomic-layer deposition (ALD), any combinations of theforegoing, or by any other suitable methods. The barrier coating 1775may also be provided by laminating a pre-formed barrier film onto thedevice 1715 using an adhesive (not shown). For example, the barriercoating 1775 may be a multi-layer coating comprising organic materials,inorganic materials, or combination of both. The barrier coating 1775may further comprise a getter material and/or a desiccant.

For comparative purposes, an example of a comparative PMOLED device 1719is illustrated in FIG. 17E. In the comparative example of FIG. 17E, aplurality of pixel definition structures 1783 are provided innon-emissive regions of the device 1719, such that when a conductivematerial is deposited using an open mask or a mask-free depositionprocess, the conductive material is deposited on both emissive regionslocated between neighboring pixel definition structures 1783 to form thecathode 1712, as well as on top of the pixel definition structures 1783to form conductive strips 1718. However, in order to ensure that eachsegment of the cathode 1712 is electrically isolated from the conductivestrips 1718, a thickness or height of the pixel definition structures1783 are formed to be greater than a thickness of the cathode 1712. Thepixel definition structures 1783 may also have an undercut profile tofurther decrease the likelihood of the cathode 1712 coming in electricalcontact with the conductive strips 1718. The barrier coating 1775 isprovided to cover the PMOLED device 1719 including the cathode 1712, thepixel definition structures 1783, and the conductive strips 1718.

In the comparative PMOLED device 1719 illustrated in FIG. 17E, thesurface onto which the barrier coating 1775 is applied is non-uniformdue to the presence of the pixel definition structures 1783. This makesthe application of the barrier coating 1775 difficult, and even upon theapplication of the barrier coating 1775, the adhesion of the barriercoating 1775 to the underlying surface may be relatively poor. Pooradhesion increases the likelihood of the barrier coating 1775 peelingoff the device 1719, particularly when the device 1719 is bent orflexed. Additionally, there is a relatively high probability of airpockets being trapped between the barrier coating 1775 and theunderlying surface during the application procedure due to thenon-uniform surface. The presence of air pockets and/or peeling of thebarrier coating 1775 can cause or contribute to defects and partial ortotal device failure, and thus is highly undesirable. These factors aremitigated or reduced in the embodiment of FIG. 17D.

While the patterned cathodes 1710 and 1712 shown in FIGS. 17 and 17B maybe used to form a cathode of an OLED device, it is appreciated that asimilar pattern may be used to form an auxiliary electrode for an OLEDdevice. Specifically, such an OLED device may be provided with a commoncathode, and an auxiliary electrode deposited on top of, or beneath, thecommon cathode such that the auxiliary electrode is in electricalcommunication with the common cathode. For example, such an auxiliaryelectrode may be implemented in an OLED device including a plurality ofemissive regions (e.g., an AMOLED device) such that the auxiliaryelectrode is formed over non-emissive regions, and not over the emissiveregions. In another example, an auxiliary electrode may be provided tocover non-emissive regions as well as at least some emissive regions ofan OLED device.

FIG. 18A depicts a portion of an OLED device 1800 including a pluralityof emissive regions 1810 a-1810 f and a non-emissive region 1820. Forexample, the OLED device 1800 may be an AMOLED device, and each of theemissive regions 1810a-1810 f may correspond to a pixel or a subpixel ofsuch a device. For sake of simplicity, FIGS. 18B-18D depict a portion ofthe OLED device 1800. Specifically, FIGS. 18B-18D show a regionsurrounding a first emissive region 1810 a and a second emissive region1810 b, which are two neighboring emissive regions. While not explicitlyillustrated, a common cathode may be provided that substantially coversboth emissive regions and non-emissive regions of the device 1800.

In FIG. 18B, an auxiliary electrode 1830 according to one embodiment isshown, in which the auxiliary electrode 1830 is disposed between the twoneighboring emissive regions 1810 a and 1810 b. The auxiliary electrode1830 is electrically connected to the common cathode (not shown).Specifically, the auxiliary electrode 1830 is illustrated as having awidth (a), which is less than a separation distance (d) between theneighboring emissive regions 1810 a and 1810 b, thus creating anon-emissive gap region on each side of the auxiliary electrode 1830.For example, such an arrangement may be desirable in the device 1800where the separation distance between the neighboring emissive regions1810 a and 1810 b are sufficient to accommodate the auxiliary electrode1830 of sufficient width, since the likelihood of the auxiliaryelectrode 1830 interfering with an optical output of the device 1800 canbe reduced by providing the non-emissive gap regions. Furthermore, suchan arrangement may be particularly beneficial in cases where theauxiliary electrode 1830 is relatively thick (e.g., greater than severalhundred nanometers or on the order a few microns thick). For example, aratio of a height or a thickness of the auxiliary electrode 1830relative to its width (namely, an aspect ratio) may be greater thanabout 0.05, such as about 0.1 or greater, about 0.2 or greater, about0.5 or greater, about 0.8 or greater, about 1 or greater, or about 2 orgreater. For example, the height or the thickness of the auxiliaryelectrode 1830 may be greater than about 50 nm, such as about 80 nm orgreater, about 100 nm or greater, about 200 nm or greater, about 500 nmor greater, about 700 nm or greater, about 1000 nm or greater, about1500 nm or greater, about 1700 nm or greater, or about 2000 nm orgreater.

In FIG. 18C, an auxiliary electrode 1832 according to another embodimentis shown. The auxiliary electrode 1832 is electrically connected to thecommon cathode (not shown). As illustrated, the auxiliary electrode 1832has substantially the same width as the separation distance between thetwo neighboring emissive regions 1810 a and 1810 b, such that theauxiliary electrode 1832 substantially fully occupies the entirenon-emissive region provided between the neighboring emissive regions1810 a and 1810 b. Such an arrangement may be desirable, for example, incases where the separation distance between the two neighboring emissiveregions 1810 a and 1810 b is relatively small, such as in a high pixeldensity display device.

In FIG. 18D, an auxiliary electrode 1834 according to yet anotherembodiment is illustrated. The auxiliary electrode 1834 is electricallyconnected to the common cathode (not shown). The auxiliary electrode1834 is illustrated as having a width (a), which is greater than theseparation distance (d) between the two neighboring emissive regions1810 a and 1810 b. Accordingly, a portion of the auxiliary electrode1834 overlaps a portion of the first emissive region 1810 a and aportion of the second emissive region 1810 b. Such an arrangement may bedesirable, for example, in cases where the non-emissive region betweenthe neighboring emissive regions 1810 a and 1810 b is not sufficient tofully accommodate the auxiliary electrode 1834 of the desired width.While the auxiliary electrode 1834 is illustrated in FIG. 18D asoverlapping with the first emissive region 1810 a to substantially thesame degree as the second emissive region 1810 b, the extent to whichthe auxiliary electrode 1834 overlaps with an adjacent emissive regionmay be modulated in other embodiments. For example, in otherembodiments, the auxiliary electrode 1834 may overlap to a greaterextent with the first emissive region 1810 a than the second emissiveregion 1810 b and vice versa. Furthermore, a profile of overlap betweenthe auxiliary electrode 1834 and an emissive region can also be varied.For example, an overlapping portion of the auxiliary electrode 1834 maybe shaped such that the auxiliary electrode 1834 overlaps with a portionof an emissive region to a greater extent than it does with anotherportion of the same emissive region to create a non-uniform overlappingregion.

In FIG. 19, an OLED device 1900 according to one embodiment isillustrated in which an emissive region 1910 and a non-emissive region1920 surrounding the emissive region 1910 are provided. A lead 1912 isillustrated as being formed in the non-emissive region 1920 of thedevice 1900. The lead 1912 is electrically connected to an electrode(not shown) covering the emissive region 1910 of the device 1900. Thelead 1912 may provide a contact point for connecting to an externalpower supply for powering such an electrode. For example, the electrodemay be connected to the external power supply via the lead 1912 by asoldering pad provided integral to the lead 1912 (to which an electricalwire may be soldered and connected to the power supply). It will beappreciated that, while not explicitly illustrated, an auxiliaryelectrode may be present and connected to the electrode covering theemissive region 1910 of the device 1900. Where such an auxiliaryelectrode is present, the lead 1912 may be directly connected to theauxiliary electrode, the electrode to which the auxiliary electrode isconnected, or both.

It will be appreciated that the lead 1912 may be provided on a sameplane as the electrode to which it is connected, or it may be providedon a different plane. For example, the lead 1912 may be connected toanother layer of the OLED device 1900, such as a backplane through oneor more vertical connections (e.g., vias).

FIG. 20 illustrates a portion of an OLED device 2000 according toanother embodiment. The OLED device 2000 includes an emissive region2010 and a non-emissive region 2020. The OLED device 2000 furtherincludes a grid-like auxiliary electrode 2030, which is in electricalcommunication with an electrode (not shown) of the device 2000. Asillustrated in FIG. 20, a first portion of the auxiliary electrode 2030is disposed within the emissive region 2010, while a second portion ofthe auxiliary electrode 2030 is disposed outside of the emissive region2010 and within the non-emissive region 2020 of the device 2000. Such anarrangement of the auxiliary electrode 2030 may allow a sheet resistanceof the electrode to be reduced while keeping the auxiliary electrode2030 from significantly interfering with an optical output of the device2000.

In some applications, it may be desirable to form a regular repeatingpattern of an auxiliary electrode over an entire device area or aportion thereof. FIGS. 21A-21D illustrate various embodiments ofrepeating units of an auxiliary electrode that may be used.Specifically, in FIG. 21A, an auxiliary electrode 2110 encompasses fourregions 2120 which are not covered by the auxiliary electrode 2110. Theauxiliary electrode 2110 is formed such that the regions 2120 arearranged in a T-shape. For example, each of the regions 2120 maysubstantially correspond to an emissive region of an OLED deviceincluding a plurality of emissive regions. Accordingly, it will beappreciated that other layers or coatings, such as a common cathode, maybe present in the regions 2120. In FIG. 21B, an auxiliary electrode 2112is formed in an inverted T-shape and encompasses four uncovered regions2122. In FIG. 21C, an auxiliary electrode 2114 is formed to encompassfour uncovered regions 2124, and, similarly in FIG. 21D, an auxiliaryelectrode 2116 is formed to encompass four uncovered regions 2126.

Potential advantages of using repeating units of an auxiliary electrode,such as those illustrated in FIGS. 21A-21D, include ease of patterningin fabricating devices. For example, a mask used in patterning anucleation promoting or nucleation inhibiting coating during theformation of the auxiliary electrode may be used repeatedly to patterndifferent portions of a device surface, thus obviating the need for morecomplex and/or larger masks.

FIG. 22 depicts a portion of an OLED device 2200 according to oneembodiment, in which the device 2200 includes a plurality of repeatingauxiliary electrode units 2230 a-d formed thereon. Specifically, eachauxiliary electrode unit 2230 a-d is L-shaped and encompasses threedistinct emitting regions 2210. For example, each emitting region 2210may correspond to a pixel or a sub-pixel of the device 2200. Asillustrated, neighboring auxiliary electrode units may interlock withone another. For example, a first auxiliary electrode unit 2230 a isformed to be in an interlocking relationship with a second auxiliaryelectrode unit 2230 b, and, similarly, a third auxiliary electrode unit2230 c is interlocked with a fourth auxiliary electrode unit 2230 d. Theauxiliary electrode units 2230 a-d are formed on a non-emissive region2220. It will be appreciated that the auxiliary electrode units 2230a-dmay be formed such that they are in direct electrical communication withone another. For example, the repeating auxiliary electrode units 2230a-d may be formed integrally during fabrication. Alternatively, theauxiliary electrode units 2230 a-d may be formed such that they areelectrically connected via a common electrode.

FIG. 23 illustrates a portion of an OLED device 2300 according toanother embodiment. In the embodiment of FIG. 23, each auxiliaryelectrode unit 2330 a, 2330 b is formed to encompass five distinctemissive regions 2310. The auxiliary electrode units 2330 a and 2330 bare formed on a non-emissive region 2320 of the device 2300. Asillustrated, a first auxiliary electrode unit 2330 a is positionedadjacent to, but not in an interlocking relationship with, a secondauxiliary electrode unit 2330 b.

In another embodiment illustrated in FIG. 24, similar auxiliaryelectrode units as those illustrated in FIG. 23 are provided. However,in FIG. 24, auxiliary electrode units 2430 a-d are arranged in aninterlocking relationship with one another. Similarly to the embodimentof FIG. 23, each auxiliary electrode unit 2430 a-d encompasses fivedistinct emissive regions 2410, and are formed on a non-emissive region2420 of a device 2400.

While various embodiments in which each auxiliary electrode unitencompasses 3, 4, or 5 emissive regions have been described andillustrated, it will be appreciated that each auxiliary electrode unitmay encompass any number of emissive regions, including 1, 2, 3, 4, 5,6, or more emissive regions.

FIG. 25 illustrates an embodiment in which an auxiliary electrode 2530is formed as a grid over an OLED device 2500. As illustrated, theauxiliary electrode is 2530 provided over a non-emissive region 2520 ofthe device 2500, such that it does not substantially cover any portionof emissive regions 2510.

FIG. 26 illustrates an embodiment in which auxiliary electrode units2630 are formed as series of elongated structures over an OLED device2600. As illustrated, the auxiliary electrode units 2630 are providedover a non-emissive region 2620 of the device 2600, such that it doesnot substantially cover any portion of emissive regions 2610. Theauxiliary electrode units 2610 are spaced apart and not physicallyconnected to one another, but rather are electrically connected via acommon electrode (not shown). As would be appreciated, the auxiliaryelectrode units 2610 which are not directly interconnected to oneanother may still provide substantial advantage by lowering an overallsheet resistance of the connected common electrode.

FIG. 27 illustrates an embodiment in which auxiliary electrode units2730 are formed in a “stair case” pattern over an OLED device 2700. Asillustrated, the auxiliary electrode units 2730 are provided over anon-emissive region 2720 of the device 2700, such that it does notsubstantially cover any portion of emissive regions 2710.

FIGS. 28A-28J illustrate various embodiments in which an auxiliaryelectrode is provided between neighboring subpixels.

In FIG. 28A, auxiliary electrode units 2830 are provided as elongatedstrips between neighboring columns of subpixels 2812. Specifically inthe embodiment of FIG. 28A, a first subpixel 2812 a, a second subpixel2812 b, and a third subpixel 2812 c collectively form a first pixel 2810a. For example, the first pixel 2810 a may be an RGB pixel, in whichcase each subpixel 2812 a-c would correspond to a red, a green, or ablue subpixel. Pixels 2810 may be arranged such that a same subpixelpattern (e.g., red, green, blue) is repeated across a display device.Specifically, a subpixel arrangement of a second pixel 2810 b and athird pixel 2810 c may be identical to that of the first pixel 2810 a.In such an arrangement, all of the subpixels 2812 in each column ofsubpixels 2812 (e.g., subpixels arranged linearly along a first axislabelled Y) may be identical in color, and the auxiliary electrode unit2830 extending substantially parallel to the first axis Y may beprovided between neighboring columns of subpixels 2812 as illustrated inFIG. 28A.

For sake of simplicity, FIG. 28B-28J are illustrated using identicalpixel and subpixel arrangements as that described in reference to FIG.28A above.

In FIG. 28B, auxiliary electrode units 2830 are illustrated as beingprovided between neighboring columns of pixels 2810. Specifically, theauxiliary electrode unit 2830 that extends substantially parallel to thefirst axis Y is provided between the first pixel 2810 a and the secondpixel 2810 b, which are aligned in the direction of a second axis X withrespect to each other. However, no auxiliary electrode unit 2830 isprovided between the first pixel 2810 a and the third pixel 2810 c,which are aligned in the direction of the first axis Y with respect toeach other. The first axis Y and the second axis X are perpendicular toone another as illustrated in the figures. It will be appreciated thatwhile the auxiliary electrode units 2830 are illustrated in FIG. 28B asextending along the first axis Y, the auxiliary electrode units 2830 mayextend along the second axis X in another embodiment.

FIG. 28C illustrates an embodiment in which an auxiliary electrode 2830is provided as a grid across a display device between neighboringsubpixels 2812. Specifically, the auxiliary electrode 2830 is providedbetween each pair of neighboring subpixels 2812 a-2812 c. Accordingly,the auxiliary electrode 2830 includes segments, which extendsubstantially parallel to the first axis Y and the second axis X to forma mesh or a grid between the subpixels 2812 a-2812 c.

In another embodiment illustrated in FIG. 28D, an auxiliary electrode2830 is provided between neighboring pixels 2810. Specifically, theauxiliary electrode 2830 is provided between the first pixel 2810 a andthe second pixel 2810 b which are aligned along the second axis X withrespect to each other, as well as between the first pixel 2810 a and thethird pixel 2810 c which are aligned along the first axis Y with respectto each other. Accordingly, the auxiliary electrode 2830 forms a mesh ora grid between the pixels 2810 a-c.

In FIG. 28E, a yet another embodiment is illustrated in which discreteauxiliary electrode units 2830 are provided between neighboringsubpixels 2812. Specifically, the auxiliary electrode units 2830 areoriented substantially parallel to the first axis Y and are providedbetween the neighboring subpixels 2812 a-c.

In FIG. 28F, an embodiment is illustrated in which discrete auxiliaryelectrode units 2830 are provided between neighboring pixels 2810.Specifically, the auxiliary electrode unit 2830 is orientedsubstantially parallel to the first axis Y and is provided between thefirst pixel 2810 a and the second pixel 2810 b, which are arrangedadjacent to each other along the second axis X.

In FIG. 28G, discrete auxiliary electrode units 2830 are providedbetween neighboring subpixels 2812 to create a grid or a mesh across adisplay device. As illustrated, the elongated auxiliary electrode units2830 which extend substantially parallel to the first axis Y aredisposed between neighboring subpixels 2812 aligned along the secondaxis X. Similarly, the elongated auxiliary electrode units 2830extending substantially parallel to the second axis X are disposedbetween neighboring subpixels 2812 aligned along the first axis Y.

In FIG. 28H, discrete auxiliary electrode units 2830 are providedbetween neighboring pixels 2810 to create a grid or a mesh across adisplay device. As illustrated, the elongated auxiliary electrode unit2830 which extends substantially parallel to the first axis Y isdisposed between neighboring pixels 2810 a and 2810 b aligned along thesecond axis X. Similarly, the elongated auxiliary electrode unit 2830extending substantially parallel to the second axis X is disposedbetween neighboring pixels 2810 a and 2810 c aligned along the firstaxis Y.

FIG. 28I illustrates another embodiment in which discrete auxiliaryelectrode units 2830 are provided between neighboring subpixels 2812 toform a grid or a mesh across a display device. The auxiliary electrodeunits 2830 each comprises a first segment extending substantiallyparallel to the first axis Y and a second segment extendingsubstantially parallel to the second axis X. The first axis Y and thesecond axis X are perpendicular to one another. In FIG. 28I, the firstsegment and the second segment are connected end-to-end to form aninverted L-shape.

FIG. 28J illustrates another embodiment in which discrete auxiliaryelectrode units 2830 are provided between neighboring subpixels 2812 toform a grid or a mesh across a display device. The auxiliary electrodeunits 2830 each comprises a first segment extending substantiallyparallel to the first axis Y and a second segment extendingsubstantially parallel to the second axis X. The first axis Y and thesecond axis X are perpendicular to one another. In FIG. 28J, the firstsegment and the second segment are connected near a mid-point of thefirst and the second segments to form a cross shape.

While auxiliary electrode units have been illustrated in certainembodiments as not being physically connected to one another, they maybe nevertheless in electrical communication with one another via acommon electrode. For example, providing discrete auxiliary electrodeunits, which are indirectly connected to one another via the commonelectrode, may still substantially lower a sheet resistance and thusincrease an efficiency of an OLED device without substantiallyinterfering with optical characteristics of the device.

Auxiliary electrodes may also be used in display devices with otherpixel or sub-pixel arrangements. For example, auxiliary electrodes maybe provided on a display device in which a diamond pixel arrangement isused. Examples of such pixel arrangements are illustrated in FIGS.29-33.

FIG. 29 is a schematic illustration of an OLED device 2900 having adiamond pixel arrangement according to one embodiment. The OLED device2900 includes a plurality of pixel definition layers (PDLs) 2930 andemissive regions 2912 (sub-pixels) disposed between neighboring PDLs2930. The emissive regions 2912 include those corresponding to firstsub-pixels 2912 a, which may, for example, correspond to greensub-pixels, second sub-pixels 2912 b, which may, for example, correspondto blue sub-pixels, and third sub-pixels 2912 c, which may, for example,correspond to red sub-pixels.

FIG. 30 is a schematic illustration of the OLED device 2900 taken alongline A-A shown in FIG. 29. As more clearly illustrated in FIG. 30, thedevice 2900 includes a substrate 2903 and a plurality of anode units2921 formed on a surface of the base substrate 2903. The substrate 2903may further include a plurality of transistors and a base substrate,which have been omitted from the figure for sake of simplicity. Anorganic layer 2915 is provided on top of each anode unit 2921 in aregion between neighboring PDLs 2930, and a common cathode 2942 isprovided over the organic layer 2915 and the PDLs 2930 to form the firstsub-pixels 2912 a. The organic layer 2915 may include a plurality oforganic and/or inorganic layers. For example, such layers may include ahole transport layer, a hole injection layer, an electroluminescencelayer, an electron injection layer, and/or an electron transport layer.A nucleation inhibiting coating 2945 is provided over regions of thecommon cathode 2942 corresponding to the first sub-pixels 2912 a toallow selective deposition of an auxiliary electrode 2951 over uncoveredregions of the common cathode 2942 corresponding to substantially planarregions of the PDLs 2930. The nucleation inhibiting coating 2945 mayalso act as an index-matching coating. A thin film encapsulation layer2961 may optionally be provided to encapsulate the device 2900.

FIG. 31 shows a schematic illustration of the OLED device 2900 takenalong line B-B indicated in FIG. 29. The device 2900 includes theplurality of anode units 2921 formed on the surface of the substrate2903, and an organic layer 2916 or 2917 provided on top of each anodeunit 2921 in a region between neighboring PDLs 2930. The common cathode2942 is provided over the organic layers 2916 and 2917 and the PDLs 2930to form the second sub-pixel 2912 b and the third sub-pixel 2912 c,respectively. The nucleation inhibiting coating 2945 is provided overregions of the common cathode 2942 corresponding to the sub-pixels 2912b and 2912 c to allow selective deposition of the auxiliary electrode2951 over uncovered regions of the common cathode 2942 corresponding tothe substantially planar regions of the PDLs 2930. The nucleationinhibiting coating 2945 may also act as an index-matching coating. Thethin film encapsulation layer 2961 may optionally be provided toencapsulate the device 2900.

FIG. 32 is a schematic illustration of an OLED device 3200 with a pixelarrangement according to another embodiment. Specifically, the device3200 includes a plurality of PDLs 3230 separating emissive regions 3212(sub-pixels). For example, first sub-pixels 3212 a may correspond togreen sub-pixels, second sub-pixels 3212 b may correspond to bluesub-pixels, and third sub-pixels 3212 c may correspond to redsub-pixels. FIG. 33 is an image of an OLED device with the pixelarrangement according to the embodiment of FIG. 32. Although not shown,the device 3200 may further include an auxiliary electrode provided overnon-emissive regions of the device 3200. For example, the auxiliaryelectrode may be disposed over regions of a common cathode correspondingto substantially planar portions of the PDLs 3230.

In another aspect according to some embodiments, a device is provided.In some embodiments, the device is an opto-electronic device. In someembodiments, the device is another electronic device or other product.In some embodiments, the device includes a substrate, a nucleationinhibiting coating, and a conductive coating. The nucleation inhibitingcoating covers a first region of the substrate. The conductive coatingcovers a second region of the substrate, and partially overlaps thenucleation inhibiting coating such that at least a portion of thenucleation inhibiting coating is exposed from, or is substantially freeof or is substantially uncovered by, the conductive coating. In someembodiments, the conductive coating includes a first portion and asecond portion, the first portion of the conductive coating covers thesecond region of the substrate, and the second portion of the conductivecoating overlaps a portion of the nucleation inhibiting coating. In someembodiments, the second portion of the conductive coating is spaced fromthe nucleation inhibiting coating by a gap. In some embodiments, thenucleation inhibiting coating includes an organic material. In someembodiments, the first portion of the conductive coating and the secondportion of the conductive coating are integrally formed with oneanother.

In another aspect according to some embodiments, a device is provided.In some embodiments, the device is an opto-electronic device. In someembodiments, the device is another electronic device or other product.In some embodiments, the device includes a substrate and a conductivecoating. The substrate includes a first region and a second region. Theconductive coating covers the second region of the substrate, andpartially overlaps the first region of the substrate such that at leasta portion of the first region of the substrate is exposed from, or issubstantially free of or is substantially uncovered by, the conductivecoating. In some embodiments, the conductive coating includes a firstportion and a second portion, the first portion of the conductivecoating covers the second region of the substrate, and the secondportion of the conductive coating overlaps a portion of the first regionof the substrate. In some embodiments, the second portion of theconductive coating is spaced from the first region of the substrate by agap. In some embodiments, the first portion of the conductive coatingand the second portion of the conductive coating are integrally formedwith one another.

FIG. 34 illustrates a portion of a device according to one embodiment.The device includes a substrate 3410 having a surface 3417. A nucleationinhibiting coating 3420 covers a first region 3415 of the surface 3417of the substrate 3410, and a conductive coating 3430 covers a secondregion 3412 of the surface 3417 of the substrate 3410. As illustrated inFIG. 34, the first region 3415 and the second region 3412 are distinctand non-overlapping regions of the surface 3417 of the substrate 3410.The conductive coating 3430 includes a first portion 3432 and a secondportion 3434. As illustrated in the figure, the first portion 3432 ofthe conductive coating 3430 covers the second region 3412 of thesubstrate 3410, and the second portion 3434 of the conductive coating3430 partially overlaps a portion of the nucleation inhibiting coating3420. Specifically, the second portion 3434 is illustrated asoverlapping the portion of the nucleation inhibiting coating 3420 in adirection that is perpendicular (or normal) to the underlying substratesurface 3417.

Particularly in the case where the nucleation inhibiting coating 3420 isformed such that its surface 3422 exhibits a relatively low initialsticking probability against a material used to form the conductivecoating 3430, there is a gap 3441 formed between the overlapping, secondportion 3434 of the conductive coating 3430 and the surface 3422 of thenucleation inhibiting coating 3420. Accordingly, the second portion 3434of the conductive coating 3430 is not in direct physical contact withthe nucleation inhibiting coating 3420, but is spaced from thenucleation inhibiting coating 3420 by the gap 3441 along the directionperpendicular to the surface 3417 of the substrate 3410 as indicated byarrow 3490. Nevertheless, the first portion 3432 of the conductivecoating 3430 may be in direct physical contact with the nucleationinhibiting coating 3420 at an interface or a boundary between the firstregion 3415 and the second region 3412 of the substrate 3410.

In some embodiments, the overlapping, second portion 3434 of theconductive coating 3430 may laterally extend over the nucleationinhibiting coating 3420 by a comparable extent as a thickness of theconductive coating 3430. For example, in reference to FIG. 34, a widthw₂ (or a dimension along a direction parallel to the surface 3417 of thesubstrate 3410) of the second portion 3434 may be comparable to athickness t₁ (or a dimension along a direction perpendicular to thesurface 3417 of the substrate 3410) of the first portion 3432 of theconductive coating 3430. For example, a ratio of w₂:t₁ may be in a rangeof about 1:1 to about 1:3, about 1:1 to about 1:1.5, or about 1:1 toabout 1:2. While the thickness t₁ would generally be relatively uniformacross the conductive coating 3430, the extent to which the secondportion 3434 overlaps with the nucleation inhibiting coating 3420(namely, w₂) may vary to some extent across different portions of thesurface 3417.

In another embodiment illustrated in FIG. 35, the conductive coating3430 further includes a third portion 3436 disposed between the secondportion 3434 and the nucleation inhibiting coating 3420. As illustrated,the second portion 3434 of the conductive coating 3430 laterally extendsover and is spaced from the third portion 3436 of the conductive coating3430, and the third portion 3436 may be in direct physical contact withthe surface 3422 of the nucleation inhibiting coating 3420. A thicknesst₃ of the third portion 3436 may be less, and, in some cases,substantially less than the thickness t₁ of the first portion 3432 ofthe conductive coating 3430. Furthermore, at least in some embodiments,a width w₃ of the third portion 3436 may be greater than the width w₂ ofthe second portion 3434. Accordingly, the third portion 3436 may extendlaterally to overlap with the nucleation inhibiting coating 3420 to agreater extent than the second portion 3434. For example, a ratio ofw₃:t₁ may be in a range of about 1:2 to about 3:1 or about 1:1.2 toabout 2.5:1. While the thickness t₁ would generally be relativelyuniform across the conductive coating 3430, the extent to which thethird portion 3436 overlaps with the nucleation inhibiting coating 3420(namely, w₃) may vary to some extent across different portions of thesurface 3417. The thickness t₃ of the third portion 3436 may be nogreater than or less than about 5% of the thickness t₁ of the firstportion 3432. For example, t₃ may be no greater than or less than about4%, no greater than or less than about 3%, no greater than or less thanabout 2%, no greater than or less than about 1%, or no greater than orless than about 0.5% of t₁. Instead of, or in addition to, the thirdportion 3436 being formed as a thin film as shown in FIG. 35, thematerial of the conductive coating 3430 may form as islands ordisconnected clusters on a portion of the nucleation inhibiting coating3420. For example, such islands or disconnected clusters may includefeatures which are physically separated from one another, such that theislands or clusters are not formed as a continuous layer.

In yet another embodiment illustrated in FIG. 36, a nucleation promotingcoating 3451 is disposed between the substrate 3410 and the conductivecoating 3430. Specifically, the nucleation promoting coating 3451 isdisposed between the first portion 3432 of the conducting coating 3430and the second region 3412 of the substrate 3410. The nucleationpromoting coating 3451 is illustrated as being disposed on the secondregion 3412 of the substrate 3410, and not on the first region 3415where the nucleation inhibiting coating 3420 is deposited. Thenucleation promoting coating 3451 may be formed such that, at aninterface or a boundary between the nucleation promoting coating 3451and the conductive coating 3430, a surface of the nucleation promotingcoating 3451 exhibits a relatively high initial sticking probability forthe material of the conductive coating 3430. As such, the presence ofthe nucleation promoting coating 3451 may promote the formation andgrowth of the conductive coating 3430 during deposition. Variousfeatures of the conducting coating 3430 (including the dimensions of thefirst portion 3432 and the second portion 3434) and other coatings ofFIG. 36 can be similar to those described above for FIG. 34-35 and arenot repeated for brevity.

In yet another embodiment illustrated in FIG. 37, the nucleationpromoting coating 3451 is disposed on both the first region 3415 and thesecond region 3412 of the substrate 3410, and the nucleation inhibitingcoating 3420 covers a portion of the nucleation promoting coating 3451disposed on the first region 3415. Another portion of the nucleationpromoting coating 3451 is exposed from, or is substantially free of oris substantially uncovered by, the nucleation inhibiting coating 3420,and the conductive coating 3430 covers the exposed portion of thenucleation promoting coating 3451. Various features of the conductingcoating 3430 and other coatings of FIG. 37 can be similar to thosedescribed above for FIG. 34-35 and are not repeated for brevity.

FIG. 38 illustrates a yet another embodiment in which the conductivecoating 3430 partially overlaps a portion of the nucleation inhibitingcoating 3420 in a third region 3419 of the substrate 3410. Specifically,in addition to the first portion 3432 and the second portion 3434, theconductive coating 3430 further includes a third portion 3480. Asillustrated in the figure, the third portion 3480 of the conductivecoating 3430 is disposed between the first portion 3432 and the secondportion 3434 of the conductive coating 3430, and the third portion 3480may be in direct physical contact with the surface 3422 of thenucleation inhibiting coating 3420. In this regard, the overlap in thethird region 3419 may be formed as a result of lateral growth of theconductive coating 3430 during an open mask or mask-free depositionprocess. More specifically, while the surface 3422 of the nucleationinhibiting coating 3420 may exhibit a relatively low initial stickingprobability for the material of the conductive coating 3430 and thus theprobability of the material nucleating on the surface 3422 is low, asthe conductive coating 3430 grows in thickness, the coating 3430 mayalso grow laterally and may cover a portion of the nucleation inhibitingcoating 3420 as illustrated in FIG. 38.

While details regarding certain features of the device and theconductive coating 3430 have been omitted in the above description forthe embodiments of FIGS. 36-38, it will be appreciated that descriptionsof various features including the gap 3441, the second portion 3434, andthe third portion 3436 of the conductive coating 3430 described inrelation to FIG. 34 and FIG. 35 would similarly apply to suchembodiments.

It will be appreciated that, while not explicitly illustrated, amaterial used to form the nucleation inhibiting coating 3420 may also bepresent to some extent at an interface between the conductive coating3430 and an underlying surface (e.g., a surface of the nucleationpromoting layer 3451 or the substrate 3410). Such material may bedeposited as a result of a shadowing effect, in which a depositedpattern is not identical to a pattern of a mask and may result in someevaporated material being deposited on a masked portion of a targetsurface. For example, such material may form as islands or disconnectedclusters, or as a thin film having a thickness that is substantiallyless than an average thickness of the nucleation inhibiting coating3420.

In some embodiments, the nucleation inhibiting coating 3420 may beremoved subsequent to deposition of the conductive coating 3430, suchthat at least a portion of an underlying surface covered by thenucleation inhibiting coating 3420 in the embodiments of FIGS. 34-38becomes exposed. For example, the nucleation inhibiting coating 3420 maybe selectively removed by etching or dissolving the nucleationinhibiting coating 3420, or using plasma or solvent processingtechniques without substantially affecting or eroding the conductivecoating 3430.

A device of some embodiments may be an electronic device, and, morespecifically, an opto-electronic device. An opto-electronic devicegenerally encompasses any device that converts electrical signals intophotons or vice versa. As such, an organic opto-electronic device canencompass any opto-electronic device where one or more active layers ofthe device are formed primarily of an organic material, and, morespecifically, an organic semiconductor material. Examples of organicopto-electronic devices include, but are not limited to, OLED devicesand OPV devices.

It will also be appreciated that organic opto-electronic devices may beformed on various types of base substrates. For example, a basesubstrate may be a flexible or rigid substrate. The base substrate mayinclude, for example, silicon, glass, metal, polymer (e.g., polyimide),sapphire, or other materials suitable for use as the base substrate.

It will also be appreciated that various components of a device may bedeposited using a wide variety of techniques, including vapordeposition, spin-coating, line coating, printing, and various otherdeposition techniques.

In some embodiments, an organic opto-electronic device is an OLEDdevice, wherein an organic semiconductor layer includes anelectroluminescent layer. In some embodiments, the organic semiconductorlayer may include additional layers, such as an electron injectionlayer, an electron transport layer, a hole transport layer, and/or ahole injection layer. For example, the OLED device may be an AMOLEDdevice, PMOLED device, or an OLED lighting panel or module. Furthermore,the opto-electronic device may be a part of an electronic device. Forexample, the opto-electronic device may be an OLED display module of acomputing device, such as a smartphone, a tablet, a laptop, or otherelectronic device such as a monitor or a television set.

FIGS. 39-41 illustrate various embodiments of an active matrix OLED(AMOLED) display device. For the sake of simplicity, various details andcharacteristics of a conductive coating at or near an interface betweenthe conductive coating and a nucleation inhibiting coating describedabove in reference to FIGS. 34-38 have been omitted. However, it will beappreciated that the features described in reference to FIGS. 34-38 mayalso be applicable to the embodiments of FIGS. 39-41.

FIG. 39 is a schematic diagram illustrating a structure of an AMOLEDdevice 3802 according to one embodiment.

The device 3802 includes a base substrate 3810, and a buffer layer 3812deposited over a surface of the base substrate 3810. A thin-filmtransistor (TFT) 3804 is then formed over the buffer layer 3812.Specifically, a semiconductor active area 3814 is formed over a portionof the buffer layer 3812, and a gate insulating layer 3816 is depositedto substantially cover the semiconductor active area 3814. Next, a gateelectrode 3818 is formed on top of the gate insulating layer 3816, andan interlayer insulating layer 3820 is deposited. A source electrode3824 and a drain electrode 3822 are formed such that they extend throughopenings formed through the interlayer insulating layer 3820 and thegate insulating layer 3816 to be in contact with the semiconductoractive layer 3814. An insulating layer 3842 is then formed over the TFT3804. A first electrode 3844 is then formed over a portion of theinsulating layer 3842. As illustrated in FIG. 39, the first electrode3844 extends through an opening of the insulating layer 3842 such thatit is in electrical communication with the drain electrode 3822. Pixeldefinition layers (PDLs) 3846 are then formed to cover at least aportion of the first electrode 3844, including its outer edges. Forexample, the PDLs 3846 may include an insulating organic or inorganicmaterial. An organic layer 3848 is then deposited over the firstelectrode 3844, particularly in regions between neighboring PDLs 3846. Asecond electrode 3850 is deposited to substantially cover both theorganic layer 3848 and the PDLs 3846. A surface of the second electrode3850 is then substantially covered with a nucleation promoting coating3852. For example, the nucleation promoting coating 3852 may bedeposited using an open mask or a mask-free deposition technique. Anucleation inhibiting coating 3854 is selectively deposited over aportion of the nucleation promoting coating 3852. For example, thenucleation inhibiting coating 3854 may be selectively deposited using ashadow mask. Accordingly, an auxiliary electrode 3856 is selectivelydeposited over an exposed surface of the nucleation promoting coating3852 using an open mask or a mask-free deposition process. For furtherspecificity, by conducting thermal deposition of the auxiliary electrode3856 (e.g., including magnesium) using an open mask or with a mask, theauxiliary electrode 3856 is selectively deposited over the exposedsurface of the nucleation promoting coating 3852, while leaving asurface of the nucleation inhibiting coating 3854 substantially free ofa material of the auxiliary electrode 3856.

FIG. 40 illustrates a structure of an AMOLED device 3902 according toanother embodiment in which a nucleation promoting coating has beenomitted. For example, the nucleation promoting coating may be omitted incases where a surface on which an auxiliary electrode is deposited has arelatively high initial sticking probability for a material of theauxiliary electrode. In other words, for surfaces with a relatively highinitial sticking probability, the nucleation promoting coating may beomitted, and a conductive coating may still be deposited thereon. Forsake of simplicity, certain details of a backplane including a TFT isomitted in describing the following embodiments.

In FIG. 40, an organic layer 3948 is deposited between a first electrode3944 and a second electrode 3950. The organic layer 3948 may partiallyoverlap with portions of PDLs 3946. A nucleation inhibiting coating 3954is deposited over a portion (e.g., corresponding to an emissive region)of the second electrode 3950, thereby providing a surface with arelatively low initial sticking probability (e.g., a relatively lowdesorption energy) for a material used to form an auxiliary electrode3956. Accordingly, the auxiliary electrode 3956 is selectively depositedover a portion of the second electrode 3950 that is exposed from thenucleation inhibiting coating 3954. As would be understood, theauxiliary electrode 3956 is in electrical communication with theunderlying second electrode 3950 so as to reduce a sheet resistance ofthe second electrode 3950. For example, the second electrode 3950 andthe auxiliary electrode 3956 may include substantially the same materialto ensure a high initial sticking probability for the material of theauxiliary electrode 3956. Specifically, the second electrode 3950 mayinclude substantially pure magnesium (Mg) or an alloy of magnesium andanother metal, such as silver (Ag). For Mg:Ag alloy, an alloycomposition may range from about 1:9 to about 9:1 by volume. Theauxiliary electrode 3956 may include substantially pure magnesium.

FIG. 41 illustrates a structure of an AMOLED device 4002 according toyet another embodiment. In the illustrated embodiment, an organic layer4048 is deposited between a first electrode 4044 and a second electrode4050 such that it partially overlaps with portions of PDLs 4046. Anucleation inhibiting coating 4054 is deposited so as to substantiallycover a surface of the second electrode 4050, and a nucleation promotingcoating 4052 is selectively deposited on a portion of the nucleationinhibiting coating 4054. An auxiliary electrode 4056 is then formed overthe nucleation promoting coating 4052. Optionally, a capping layer 4058may be deposited to cover exposed surfaces of the nucleation inhibitingcoating 4054 and the auxiliary electrode 4056.

While the auxiliary electrode 3856 or 4056 is illustrated as not beingin direct physical contact with the second electrode 3850 or 4050 in theembodiments of FIGS. 39 and 41, it will be understood that the auxiliaryelectrode 3856 or 4056 and the second electrode 3850 or 4050 maynevertheless be in electrical communication. For example, the presenceof a relatively thin film (e.g., up to about 100 nm) of a nucleationpromoting material or a nucleation inhibiting material between theauxiliary electrode 3856 or 4056 and the second electrode 3850 or 4050may still sufficiently allow a current to pass therethrough, thusallowing a sheet resistance of the second electrode 3850 or 4050 to bereduced.

FIG. 42 illustrates a structure of an AMOLED device 4102 according toyet another embodiment in which an interface between a nucleationinhibiting coating 4154 and an auxiliary electrode 4156 is formed on aslanted surface created by PDLs 4146. The device 4102 includes anorganic layer 4148 deposited between a first electrode 4144 and a secondelectrode 4150, and the nucleation inhibiting coating 4154 is depositedover a portion of the second electrode 4150 which corresponds to anemissive region of the device 4102. The auxiliary electrode 4156 isdeposited over portions of the second electrode 4150 that are exposedfrom the nucleation inhibiting coating 4154.

While not shown, the AMOLED device 4102 of FIG. 42 may further include anucleation promoting coating disposed between the auxiliary electrode4156 and the second electrode 4150. The nucleation promoting coating mayalso be disposed between the nucleation inhibiting coating 4154 and thesecond electrode 4150, particularly in cases where the nucleationpromoting coating is deposited using an open mask or a mask-freedeposition process.

FIG. 43 illustrates a portion of an AMOLED device 4300 according to yetanother embodiment wherein the AMOLED device 4300 includes a pluralityof light transmissive regions. As illustrated, the AMOLED device 4300includes a plurality of pixels 4321 and an auxiliary electrode 4361disposed between neighboring pixels 4321. Each pixel 4321 includes asubpixel region 4331, which further includes a plurality of subpixels4333, 4335, 4337, and a light transmissive region 4351. For example, thesubpixel 4333 may correspond to a red subpixel, the subpixel 4335 maycorrespond to a green subpixel, and the subpixel 4337 may correspond toa blue subpixel. As will be explained, the light transmissive region4351 is substantially transparent to allow light to pass through thedevice 4300.

FIG. 44 illustrates a cross-sectional view of the device 4300 takenalong line A-A as indicated in FIG. 43. Briefly, the device 4300includes a base substrate 4310, a TFT 4308, an insulating layer 4342,and an anode 4344 formed on the insulating layer 4342 and in electricalcommunication with the TFT 4308. A first PDL 4346 a and a second PDL4346 b are formed over the insulating layer 4342 and cover edges of theanode 4344. One or more organic layers 4348 are deposited to cover anexposed region of the anode 4344 and portions of the PDLs 4346 a, 4346b. A cathode 4350 is then deposited over the one or more organic layers4348. Next, a nucleation inhibiting coating 4354 is deposited to coverportions of the device 4300 corresponding to the light transmissiveregion 4351 and the subpixel region 4331. The entire device surface isthen exposed to magnesium vapor flux, thus causing selective depositionof magnesium over an uncoated region of the cathode 4350. In this way,the auxiliary electrode 4361, which is in electrical contact with theunderlying cathode 4350, is formed.

In the device 4300, the light transmissive region 4351 is substantiallyfree of any materials which may substantially affect the transmission oflight therethrough. In particular, the TFT 4308, the anode 4344, and theauxiliary electrode 4361 are all positioned within the subpixel region4331 such that these components do not attenuate or impede light frombeing transmitted through the light transmissive region 4351. Sucharrangement allows a viewer viewing the device 4300 from a typicalviewing distance to see through the device 4300 when the pixels are offor are non-emitting, thus creating a transparent AMOLED display.

While not shown, the AMOLED device 4300 of FIG. 44 may further include anucleation promoting coating disposed between the auxiliary electrode4361 and the cathode 4350. The nucleation promoting coating may also bedisposed between the nucleation inhibiting coating 4354 and the cathode4350.

In other embodiments, various layers or coatings, including the organiclayers 4348 and the cathode 4350, may cover a portion of the lighttransmissive region 4351 if such layers or coatings are substantiallytransparent. Alternatively, the PDLs 4346 a, 4346 b may not be providedin the light transmissive region 4351, if desired.

It will be appreciated that pixel and subpixel arrangements other thanthe arrangement illustrated in FIGS. 43 and 44 may also be used, and theauxiliary electrode 4361 may be provided in other regions of a pixel.For example, the auxiliary electrode 4361 may be provided in the regionbetween the subpixel region 4331 and the light transmissive region 4351,and/or be provided between neighbouring subpixels, if desired.

In the foregoing embodiments, a nucleation inhibiting coating may, inaddition to inhibiting nucleation and deposition of a conductivematerial (e.g., magnesium) thereon, act to enhance an out-coupling oflight from a device. Specifically, the nucleation inhibiting coating mayact as an index-matching coating and/or an anti-reflective coating.

A barrier coating (not shown) may be provided to encapsulate the devicesillustrated in the foregoing embodiments depicting AMOLED displaydevices. As will be appreciated, such a barrier coating may inhibitvarious device layers, including organic layers and a cathode which maybe prone to oxidation, from being exposed to moisture and ambient air.For example, the barrier coating may be a thin film encapsulation formedby printing, CVD, sputtering, ALD, any combinations of the foregoing, orby any other suitable methods. The barrier coating may also be providedby laminating a pre-formed barrier film onto the devices using anadhesive. For example, the barrier coating may be a multi-layer coatingcomprising organic materials, inorganic materials, or combination ofboth. The barrier coating may further comprise a getter material and/ora desiccant in some embodiments.

A sheet resistance specification for a common electrode of an AMOLEDdisplay device may vary according to a size of the display device (e.g.,a panel size) and a tolerance for voltage variation. In general, thesheet resistance specification increases (e.g., a lower sheet resistanceis specified) with larger panel sizes and lower tolerances for voltagevariation across a panel.

The sheet resistance specification and an associated thickness of anauxiliary electrode to comply with the specification according to anembodiment were calculated for various panel sizes and plotted in FIG.56. The sheet resistances and the auxiliary electrode thicknesses werecalculated for voltage tolerances of 0.1 V and 0.2 V. Specifically, avoltage tolerance indicates a difference in voltage that would besupplied to pixels at an edge and those at a center of a panel tocompensate for a combined IR drop of a transparent electrode and anauxiliary electrode as explained above. For the purpose of thecalculation, an aperture ratio of 0.64 was assumed for all display panelsizes.

The specified thickness of the auxiliary electrode at example panelsizes are summarized in Table 2 below.

TABLE 2 Specified thickness of auxiliary electrode for various panelsizes Panel Size (inch) 9.7 12.9 15.4 27 65 Specified @0.1 V 132 239 3351100 6500 Thickness (nm) @0.2 V  67 117 174  516 2800

As will be understood, various layers and portions of a backplane,including a thin-film transistor (TFT) (e.g., TFT 3804 shown in FIG. 39)may be fabricated using a variety of suitable materials and processes.For example, the TFT may be fabricated using organic or inorganicmaterials, which may be deposited and/or processed using techniques suchas CVD, PECVD, laser annealing, and PVD (including sputtering). As wouldbe understood, such layers may be patterned using photolithography,which uses a photomask to expose selective portions of a photoresistcovering an underlying device layer to UV light. Depending on the typeof photoresist used, exposed or unexposed portions of the photomask maythen be washed off to reveal desired portion(s) of the underlying devicelayer. A patterned surface may then be etched, chemically or physically,to effectively remove an exposed portion of the device layer.

Furthermore, while a top-gate TFT has been illustrated and described incertain embodiments above, it will be appreciated that other TFTstructures may also be used. For example, the TFT may be a bottom-gateTFT. The TFT may be an n-type TFT or a p-type TFT. Examples of TFTstructures include those utilizing amorphous silicon (a-Si), indiumgallium zinc oxide (IGZO), and low-temperature polycrystalline silicon(LTPS).

Various layers and portions of a frontplane, including electrodes, oneor more organic layers, a pixel definition layer, and a capping layermay be deposited using any suitable deposition processes, includingthermal evaporation and/or printing. It will be appreciated that, forexample, a shadow mask may be used as appropriate to produce desiredpatterns when depositing such materials, and that various etching andselective deposition processes may also be used to pattern variouslayers. Examples of such methods include, but are not limited to,photolithography, printing (including ink or vapor jet printing andreel-to-reel printing), OVPD, and LITI patterning.

While certain embodiments have been described above with reference toselectively depositing a conductive coating to form a cathode or anauxiliary electrode for a common cathode, it will be understood thatsimilar materials and processes may be used to form an anode or anauxiliary electrode for an anode in other embodiments.

EXAMPLES

Aspects of some embodiments will now be illustrated and described withreference to the following examples, which are not intended to limit thescope of the present disclosure in any way.

As used in the examples herein, a reference to a layer thickness of amaterial refers to an amount of the material deposited on a targetsurface (or target region(s) of the surface in the case of selectivedeposition), which corresponds to an amount of the material to cover thetarget surface with an uniformly thick layer of the material having thereferenced layer thickness. By way of example, depositing a layerthickness of 10 nm indicates that an amount of the material deposited onthe surface corresponds to an amount of the material to form anuniformly thick layer of the material that is 10 nm thick. It will beappreciated that, for example, due to possible stacking or clustering ofmolecules or atoms, an actual thickness of the deposited material may benon-uniform. For example, depositing a layer thickness of 10 nm mayyield some portions of the deposited material having an actual thicknessgreater than 10 nm, or other portions of the deposited material havingan actual thickness less than 10 nm. A certain layer thickness of amaterial deposited on a surface can correspond to an average thicknessof the deposited material across the surface.

Molecular structures of certain materials used in the illustrativeexamples are provided below.

Example 1

In order to characterize an interface between a nucleation inhibitingcoating and an adjacent magnesium coating, a series of samples havingvarying layer thicknesses of the nucleation inhibiting coating and themagnesium coating were prepared and analyzed. Samples were prepared in ahigh vacuum deposition system with cryo-pumped processing chamber andturbo-molecular pumped load lock chamber using stainless steel shadowmasks. Materials were thermally deposited from Knudsen cells (K-cells)using quartz crystal microbalances (QCMs) to monitor a deposition rate.A base pressure of the system was less than about 10⁻⁵ Pa, with apartial pressure of H₂O less than about 10⁻⁸ Torr during deposition.Magnesium was deposited at a source temperature of about 430-570° C. ata deposition rate of about 1-5 Å/sec. SEM micrographs were taken using aHitachi S-5200.

The samples were prepared by first depositing about 30 nm of silver overa silicon substrate using thermal deposition. A nucleation inhibitingcoating was then selectively deposited on a region of the silver surfaceusing a shadow mask. In all of the samples,3-(4-biphenyl)-4-phenyl-5-tert-butylphenyl-1,2,4-triazole (TAZ) was usedto form the nucleation inhibiting coating. Once the nucleationinhibiting coating was deposited, substantially pure magnesium (about99.99% purity) was deposited using open mask deposition. Morespecifically, both an exposed silver surface and a nucleation inhibitingcoating surface were subjected to an evaporated magnesium flux duringthe open mask deposition. The layer thicknesses of the nucleationinhibiting coating and associated deposition rates are summarized inTable 3 below. All depositions were conducted under vacuum (about 10⁻⁴to about 10⁻⁶ Pa), and the layer thicknesses and deposition rates weremonitored using a calibrated quartz crystal microbalance (QCM).

TABLE 3 TAZ and magnesium thicknesses and deposition rates TAZ Mg TAZdeposition Mg deposition thickness thickness rate rate Sample No. (nm)(nm) (Å/s) (Å/s) Sample 1 10 1160 0.2 2 Sample 2 100 500 0.7 2

The samples were analyzed using scanning electron microscopy (SEM) andenergy-dispersive X-ray spectroscopy (EDX).

FIG. 45A is a SEM image of a top view of Sample 1. A first region 4501of the image corresponds to a region over which magnesium has beendeposited on top of the exposed silver surface, and a second region 4503corresponds to a region covered by the nucleation inhibiting coating(TAZ). FIGS. 45B and 45C show a magnified top view of a portion ofSample 1 as shown in FIG. 45A. Based on the EDX elemental analysis, thepresence of magnesium was not detected over a majority of the secondregion 4503. However, the formation of magnesium-containing islands orclusters 4505 was observed (see FIG. 45A), and the presence of magnesiumin those islands 4503 was confirmed based on the EDX elemental analysis.

FIGS. 45D and 45E are SEM cross-sectional images of Sample 1, whichshows an interface between the magnesium coating (the region 4501) andthe nucleation inhibiting coating (region 4503). The underlyingsubstrate 4510 can also be seen in these images.

FIGS. 45F and 45G are additional SEM cross-sectional images of Sample 1,taken at a different portion of the sample than FIGS. 45D and 45E.

As can be seen from FIGS. 45D-45G, the magnesium coating (the region4501) includes a portion extending laterally over the nucleationinhibiting coating (the region 4503) in a partially overlapping regionnear the interface of the magnesium coating and the nucleationinhibiting coating. Specifically, the portion of the magnesium coatingcan be seen as forming an overhang which is not in direct contact withthe surface of the nucleation inhibiting coating, thus creating a gapbetween the magnesium coating and the nucleation inhibiting coating atthe interface.

FIG. 45H shows an EDX spectra taken from the first region 4501 and thesecond region 4503 of Sample 1. As can be seen from the plot of FIG.45H, a peak corresponding to magnesium is clearly observed in thespectrum taken from the first region 4501, whereas no noticeable peak isdetected in the spectrum taken from the second region 4503. The EDXmeasurements were taken at 5 keV over a sample area of about 2 pmt.

FIG. 46A is a SEM image of a top view of Sample 2. A first region 4601of the image corresponds to a region over which magnesium has beendeposited on top of the exposed silver surface, and a second region 4603corresponds to a region covered by the nucleation inhibiting coating(TAZ). A magnified image of a portion of FIG. 46A is shown in FIG. 46B,and a further magnified image of a portion of FIG. 46B is shown in FIG.46C. A cross-sectional profile of the sample is shown in the images ofFIGS. 46D, 46E, and 46F, which also shows the substrate 4610. As can beseen in the images of FIGS. 46B-F, there is a relatively thin film orlayer of magnesium 4607 deposited near the interface between themagnesium coating (the region 4601) and the TAZ coating (the region4603). The presence of magnesium in the thin film 4607 was confirmedthrough EDX measurements. Also, the formation of magnesium-containingislands or clusters 4605 was observed (see FIG. 46A).

FIG. 46G shows an EDX spectra taken from the first region 4601 and thesecond region 4603 of Sample 2. As can be seen from the plot of FIG.46G, a peak corresponding to magnesium is clearly observed in thespectrum taken from the first region 4601, whereas no noticeable peak isdetected in the spectrum taken from the second region 4603. The EDXmeasurements were taken at 5 keV over a sample area of about 2 pmt.

FIG. 46H shows a linear EDX scan of the magnesium spectrum taken along ascan line of Sample 2. The EDX spectrum is overlaid on top of thecorresponding SEM image to show the portion of the sample from which theEDX spectrum was obtained. As can be seen, the intensity of themagnesium spectrum begins to decrease at about 1.7 μm from the interfacebetween the first region 4601 and the thin film 4607. This observationis consistent with the cross-sectional profile observed for the sample(e.g., FIG. 46D), which shows a thickness of the magnesium coatinggradually decreasing or tapering near the interface.

Example 2

To measure properties of various materials for use as a nucleationinhibiting coating or a nucleation promoting coating, a series ofexperiments were conducted using a set of quartz crystal microbalances(QCMs).

As will be understood, a QCM can be used to monitor a rate of depositionin a thin film deposition process. Briefly, such monitoring is conductedby measuring a change in frequency of a quartz crystal resonator causedby addition or removal of a material on a surface of the resonator.

FIG. 47 is a schematic diagram illustrating an experimental set-up formeasuring a deposition profile of magnesium on surfaces of QCMs. Asillustrated, an evaporation chamber 4701 includes a first evaporationsource 4710 and a second evaporation source 4712. A pair of QCMs 4731and 4741 are positioned inside the chamber 4701 with a resonator surfaceof each of the QCMs 4731 and 4741 facing towards the sources 4710 and4712. A sample shutter 4721 and a source shutter 4725 are disposedbetween the QCMs 4731 and 4741 and the evaporation sources 4710 and4712. The sample shutter 4721 and the source shutter 4725 are moveableshutters adapted to control a flux of vapor incident on the QCMs 4731and 4741 and the flux of vapor exiting from the sources 4710 and 4712,respectively.

In the illustrated example set up, the first QCM 4731, which will alsobe referred to herein as a “reference QCM”, serves as a baseline againstwhich a deposition profile of magnesium on the second QCM 4741, whichwill also be referred to herein as a “sample QCM”, is compared.Optically polished quartz crystals obtained from LapTech Precision Inc.(part number: XL1252; frequency: 6.000 MHz; AT_(1;) center: 5.985 MHz;diameter: 13.97 mm±3 mm; optically polished) were used as the referenceQCM and the sample QCM in each experiment.

Each experiment was conducted as follows. First, the reference QCM 4731and the sample QCM 4741 were positioned inside the evaporation chamber4701 as illustrated in FIG. 47. The chamber 4701 was then pumped downuntil the chamber pressure was below about 10⁻⁵ Pa. The sample shutter4721 was then actuated such that the resonator surfaces of both thereference QCM 4731 and the sample QCM 4741 were masked. The firstevaporation source 4710 was then initiated to start evaporation of anucleation promoting or inhibiting material (also referred to as a“nucleation modifying material” herein). Once a stable evaporation ratewas achieved, the sample shutter 4721 was moved such that the resonatorsurface of the sample QCM 4741 became exposed to the vapor flux whilekeeping the surface of the reference QCM 4731 unexposed, thus allowingthe nucleation modifying material to be deposited on the surface of thesample QCM 4741. Upon depositing a desired layer thickness of thenucleation modifying material on the surface of the sample QCM 4741, thesource shutter 4725 was actuated to block the vapor flux exiting thefirst source 4710, thus preventing further deposition. The first source4710 was then shut off.

Next, the second evaporation source 4712 was initiated to startevaporation of magnesium. The shutter 4721 was used to cover the QCMs4731 and 4741 until a stable deposition rate was reached. Once thestable deposition rate was reached, the shutter 4721 was actuated touncover both the modified surface of the sample QCM 4741 and the surfaceof the reference QCM 4731, such that magnesium vapor was incident on thesurfaces of both QCMs 4731 and 4741. The resonant frequencies of theQCMs 4731 and 4741 were monitored to determine the deposition profilesof magnesium on each of the QCMs 4731 and 4741.

Various nucleation modifying materials, including those that can be usedto form a nucleation inhibiting coating, were deposited on the resonatorsurface of the sample QCM 4741 to form a nucleation modifying coatingthereon. By repeating the above experimental procedure using the chamberconfiguration illustrated in FIG. 47 for each nucleation modifyingmaterial, the deposition rate of magnesium on various surfaces wasanalyzed. The following materials were used to form a nucleationmodifying coating:3-(4-biphenyl)-4-phenyl-5-tert-butylphenyl-1,2,4-triazole (TAZ);aluminum (III) bis(2-methyl-8-quninolinato)-4-phenylphenolate (BAlq);2-(4-(9,10-di(naphthalene-2-yl)anthracene-2-yl)phenyl)-1-phenyl-1H-benzo-[D]imidazole(LG201); 8-hydroxyquinoline lithium (Liq); andN(diphenyl-4-yl)9,9-dimethyl-N-(4(9-phenyl-9H-carbazol-3-yl)phenyl)-9H-fluorene-2-amine(HT211).

FIG. 57 is a log-log plot showing a layer thickness of magnesiumdeposited on the reference QCM surface (reference layer thickness, or“deposited thickness” as labeled in FIG. 57) against a layer thicknessof magnesium deposited on the sample QCM surface (sample layerthickness, or “average film thickness” as labeled in FIG. 57). In eachcase, the reference QCM surface was pre-coated with substantially puresilver prior to conducting the experiments.

Based on the plot of FIG. 57, the layer thicknesses of magnesiumdeposited on both QCM surfaces and thus the deposition rate of magnesiumas a result of exposing the surfaces to the same magnesium vapor fluxcan be determined. In particular, by comparing the deposition rate ofmagnesium on the sample QCM surface to that on the reference QCM surfaceduring the formation of a relatively thin layer of magnesium on thesample QCM surface (namely, during initial stages of deposition of up to1 nm or 10 nm in layer thickness), the nucleation inhibiting propertiesof a coating present on the sample QCM surface may be determined. Forease of discussion, the layer thickness of magnesium deposited on thesample QCM surface will be referred to as the sample layer thickness,and the layer thickness of magnesium deposited on the reference QCMsurface will be referred to as the reference layer thickness.

For certain experiments, the reference layer thickness corresponding tothe sample layer thickness at 1 nm and 10 nm for various samples issummarized in Table 4 below. Specifically, the reference layer thicknessprovided in Table 4 corresponds to the layer thickness of magnesiumdeposited on the reference QCM surface in the same time period for a 1nm or 10 nm layer thickness to be deposited on the sample QCM surfacefor each sample. Organic materials were deposited at a deposition rateof about 1 Å/sec at a vacuum pressure of about 10⁻⁵ Pa. Magnesium wasdeposited at a deposition rate of about 2 Å/sec at a source temperatureof about 520-530° C. and a vacuum pressure of about 10⁻⁵ Pa.

TABLE 4 Summary of results of the sample layer thickness andcorresponding reference layer thickness Nucleation Thickness ofThickness of Mg Modifying Mg on sample on reference QCM Material QCMsurface (nm) surface (nm) TAZ 1 2158 BAlq 1 104 LG201 1 31 Liq 1 62HT211 1 33

Based on the above, it can be seen that the reference layer thicknesswhich was deposited when the sample layer thickness of 1 nm was reachedvaried substantially depending on the nucleation modifying materialcovering the sample QOM surface. A threshold sample layer thickness of 1nm was selected in this example to determine the relative depositionrates during the initial stage of film formation on the sample QCMsurface. It was observed that, since the reference QCM surface waspre-coated with silver, the deposition rate of magnesium on thereference QCM surface remained relatively constant.

A relatively thick coating of magnesium in excess of 2000 nm wasdeposited on the reference QCM before the sample layer thickness of 1 nmwas reached for the sample QCM coated with TAZ. A reference layerthickness of 104 nm was deposited before the sample layer thickness of 1nm was reached for the sample QCM coated with BAlq. However, arelatively thin coating of magnesium with a layer thickness less than 62nm was deposited on the reference QCM before the threshold thickness wasreached for the sample QCMs coated with LG201, Liq, or HT211.

As will be appreciated, a greater selectivity can generally be achievedduring conductive coating deposition by using a nucleation modifyingcoating exhibiting a relatively high reference layer thickness, and thusa relatively low initial deposition rate and sticking probability. Forexample, a nucleation modifying coating exhibiting a high referencelayer thickness may be an effective nucleation inhibiting coating, andmay be used to cover region(s) of a target surface, such that when thetarget surface is exposed to magnesium vapor flux, magnesium selectivelyforms over uncovered region(s) of the target surface, with a surface ofthe nucleation inhibiting coating remaining substantially free of orsubstantially uncovered by magnesium. For example, a nucleationmodifying coating exhibiting a reference layer thickness of at least orgreater than about 80 nm at a threshold sample layer thickness of 1 nmmay be used as a nucleation inhibiting coating. For example, anucleation modifying coating exhibiting a reference layer thickness ofat least or greater than about 100 nm, at least or greater than about200 nm, at least or greater than about 500 nm, at least or greater thanabout 700 nm, at least or greater than about 1000 nm, at least orgreater than about 1500 nm, at least or greater than about 1700 nm, orat least or greater than about 2000 nm at 1 nm threshold thickness maybe used as a nucleation inhibiting coating. In other words, an initialdeposition rate of magnesium on the reference surface may be at least orgreater than about 80 times, at least or greater than about 100 times,at least or greater than about 200 times, at least or greater than about500 times, at least or greater than about 700 times, at least or greaterthan about 1000 times, at least or greater than about 1500 times, atleast or greater than about 1700 times, or at least or greater thanabout 2000 times an initial deposition rate of magnesium on a surface ofthe nucleation inhibiting coating.

FIG. 58 is a log-log plot of sticking probability of magnesium vapor onthe sample QCM surface versus a layer thickness of magnesium depositedon the sample QCM surface.

The sticking probability was derived based on the following equation:

$S = \frac{N_{ads}}{N_{total}}$

wherein N_(ads) is a number of adsorbed monomers that are incorporatedinto a magnesium coating on the surface of the sample QCM, and N_(total)is a total number of impinging monomers on the surface, which wasdetermined based on monitoring the deposition of magnesium on thereference QCM.

As can be seen from the plot of FIG. 58, the sticking probabilitygenerally increases as more magnesium is deposited on the surface. Forthe purpose of achieving selective deposition of a magnesium coating, anucleation inhibiting coating exhibiting a relatively low initialsticking probability (e.g., a low sticking probability during an initialdeposition stage) is desirably used. More specifically, an initialsticking probability of this example refers to the sticking probabilitymeasured upon depositing an amount of magnesium corresponding to forminga close-packed magnesium layer with an average thickness of 1 nm on asurface of a nucleation inhibiting coating. The sticking probabilitymeasured upon deposition of 1 nm layer thickness of magnesium on variousnucleation inhibiting coating surfaces are summarized in Table 5 below.

TABLE 5 Summary of results of sticking probability Nucleation Stickingprobability upon Inhibiting Material deposition of 1 nm of Mg TAZ <0.001BAlq 0.013 LG201 0.042 Liq 0.045 HT211 0.064

Based on the experiments, coatings exhibiting an initial stickingprobability of no greater than or less than about 0.03 (or 3%) withrespect to magnesium vapor may act as a nucleation inhibiting coating.As would be understood, nucleation inhibiting coatings with lowerinitial sticking probability may be more desirable for someapplications, such as for achieving deposition of a relatively thickmagnesium coating. For example, coatings with an initial stickingprobability of no greater than or less than about 0.02, no greater thanor less than about 0.01, no greater than or less than about 0.08, nogreater than or less than about 0.005, no greater than or less thanabout 0.003, no greater than or less than about 0.001, no greater thanor less than about 0.0008, no greater than or less than about 0.0005, orno greater than or less than about 0.0001 may be used as a nucleationinhibiting coating. For example, such nucleation inhibiting coating mayinclude those formed by depositing BAlq and/or TAZ.

Example 3

In order to characterize a correlation between a lateral growth of amagnesium coating near interfaces with adjacent coatings and a verticalgrowth of the magnesium coating, a series of samples with varyingmagnesium and TAZ layer thicknesses were prepared.

The samples were prepared by first depositing about 30 nm of silver overa silicon substrate using thermal deposition. A nucleation inhibitingcoating was then selectively deposited on regions of the silver surfaceusing a shadow mask. In all of the samples,3-(4-biphenyl)-4-phenyl-5-tert-butylphenyl-1,2,4-triazole (TAZ) was usedto form the nucleation inhibiting coating. Once the nucleationinhibiting coating was deposited, substantially pure magnesium (about99.99% purity) was deposited using open mask deposition such that bothan exposed silver surface and a nucleation inhibiting coating surfacewere subjected to an evaporated magnesium flux during the open maskdeposition. All depositions were conducted under vacuum (about 10⁻⁴ toabout 10⁻⁶ Pa). Magnesium was deposited at a rate of about 2 Å/s.

FIG. 49 is a schematic diagram illustrating the samples that wereprepared. As shown, portions 4901 and 4903 of the nucleation inhibitingcoating were selectively deposited on regions of the silver surface, andthe magnesium coating 4907 was deposited between the portions 4901 and4903. For ease of discussion, the silicon substrate and the silver layerhave been omitted from the diagram of FIG. 49. A lateral distance of theexposed silver surface located between the portions 4901 and 4903 of thenucleation inhibiting coating is shown as d, and a width of themagnesium coating 4907 is shown as d+Δd. In this way, a lateral growthdistance of the magnesium coating 4907 can be determined by subtractingthe lateral distance of the exposed silver surface from the width of themagnesium coating 4907. Both d and d+Δd were measured by conducting ananalysis of top view SEM images of the samples. The layer thickness ofmagnesium, h, was monitored using a quartz crystal microbalance (QCM)during the deposition process.

The lateral growth distance (Δd) measured for the samples with varyingmagnesium layer thicknesses (h) and nucleation inhibiting layerthicknesses are summarized in Table 6 below. The measurement accuracy ofAd is about 0.5 μm.

TABLE 6 Lateral growth distance of Mg for various Mg and TAZ layerthicknesses h (μm) Δd (μm) (TAZ 10 nm) Δd (μm) (TAZ 100 nm) 0.25 <0.5<0.5 0.75 2.5 <0.5 1.5 3.5 —

As can be observed from the above results, no detectable amount oflateral growth was observed in the samples prepared with a relativelythick TAZ coating. Specifically, no lateral growth was detected for thesamples prepared with 100 nm of TAZ nucleation inhibiting coating and0.25 μm and 0.75 μm of magnesium coating.

For the samples prepared with a relatively thin (10 nm layer thickness)TAZ coating, no lateral growth was detected for the sample with 0.25 μmthick magnesium coating. However, for the samples prepared with thickermagnesium coatings, lateral growth of magnesium was observed.Specifically, the sample prepared with 10 nm thick TAZ nucleationinhibiting coating and 0.75 μm thick magnesium coating exhibited lateralmagnesium growth of about 2.5 μm, and the sample prepared with 10 nmthick TAZ nucleation inhibiting coating and 1.5 μm thick magnesiumcoating exhibited lateral growth of about 3.5 μm.

Example 4

A sample was prepared using another nucleation inhibiting coatingincluding BAlq.

Specifically, the sample was fabricated according to the followingstructure: silicon base substrate/LG201 (40 nm)/Mg:Ag (20 nm)/BAlq (500nm)/Mg (300 nm). Specifically, about 40 nm of2-(4-(9,10-di(naphthalene-2-yl)anthracene-2-yl)phenyl)-1-phenyl-1H-benzo-[D]imidazole(LG201) was deposited on a silicon substrate, followed by about 20 nm ofMg:Ag (including Mg:Ag in about 1:9 proportion by volume). Thenucleation inhibiting coating in the form of about 500 nm of aluminum(III) bis(2-methyl-8-quninolinato)-4-phenylphenolate (BAlq) was thenselectively deposited over regions of the Mg:Ag surface. Once thenucleation inhibiting coating was deposited, substantially puremagnesium (about 99.99% purity) was deposited using open mask depositionsuch that both an exposed Mg:Ag surface and a nucleation inhibitingcoating surface were subjected to an evaporated magnesium flux duringthe open mask deposition. All depositions were conducted under vacuum(about 10⁻⁴ to about 10⁻⁶ Pa). The magnesium coating was deposited atrate of about 3.5 Å/s.

FIG. 50A is a SEM image of a top view of the sample prepared using theBAlq nucleation inhibiting coating. A first region 5003 corresponds to aregion where the BAlq coating was present and thus no significant amountof magnesium was deposited, and a second region 5001 corresponds to aregion where magnesium was deposited. FIGS. 50C and 50D show a magnifiedview of regions 5007 and 5005, respectively. FIG. 50B shows a magnifiedview of an interface between the first region 5003 and the second region5001.

As can be seen in FIG. 50B, there were a number of islands 5011 formednear the interface. Specifically, the islands 5011 are generallydisconnected magnesium-containing clusters which form on the surface ofthe nucleation inhibiting coating. For example, it is postulated thatislands may include magnesium and/or magnesium oxide.

FIG. 50C shows the magnified view of the region 5007 in FIG. 50A, whichis a region representative of a “bulk” of the magnesium coating formedby the process. FIG. 50D shows the magnified view of the region 5005,which is near the interface between the first region 5003 and the secondregion 5001. As can be seen, a morphology of the magnesium coating nearthe interface differs from that in the bulk of the coating.

FIG. 50E further shows a cross-sectional SEM image of the sample, wherethe islands 5011 are shown on the surface of the nucleation inhibitingcoating.

Example 5 (Comparative Example A)

A comparative sample was prepared to characterize a structure formedusing a material exhibiting relatively poor nucleation inhibitingproperties (e.g., a nucleation inhibiting coating exhibits a relativelyhigh initial sticking coefficient for magnesium vapor).

The comparative sample was fabricated according to the followingstructure: silicon base substrate/LG201 (40 nm)/Mg:g(20 nm)/HT211 (500nm)/Mg (300 nm). Specifically, about 40 nm of2-(4-(9,10-di(naphthalene-2-yl)anthracene-2-yl)phenyl)-1-phenyl-1H-benzo-[D]imidazole(LG201) was deposited on a silicon substrate, followed by about 20 nm ofMg:Ag (about 1:9 by volume). The nucleation inhibiting coating in theform of about 500 nm ofN(diphenyl-4-yl)9,9-dimethyl-N-(4(9-phenyl-9H-carbazol-3-yl)phenyl)-9H-fluorene-2-amine(HT211) was then selectively deposited over regions of the Mg:Agsurface. Once the nucleation inhibiting coating was deposited,substantially pure magnesium (about 99.99% purity) was deposited usingopen mask deposition such that both an exposed Mg:Ag surface and anucleation inhibiting coating surface were subjected to an evaporatedmagnesium flux during the open mask deposition. All depositions wereconducted under vacuum (about 10⁻⁴ to about 10⁻⁶ Pa). The magnesiumcoating was deposited at rate of about 3.5 Å/s.

FIG. 51A shows a top view SEM image of the comparative sample, where afirst region 5103 corresponds to a region over which the nucleationinhibiting coating in the form of HT211 was deposited, and a secondregion 5101 corresponds to a region where the magnesium coating wasformed. As can be seen, a significant amount of magnesium in the firstregion 5103 can be clearly observed.

FIG. 51B shows a cross-sectional SEM image of the comparative sample. Anapproximate interface between the first region 5103 and the secondregion 5101 is indicated using a dotted line.

Example 6 (Comparative Example B)

Another comparative sample was prepared to determine a profile of amagnesium coating deposited on a surface using a shadow mask technique.

The comparative sample was fabricated by depositing about 30 nm layerthickness of silver on top of a silicon wafer, followed by shadow maskdeposition of about 800 nm layer thickness of magnesium. Specifically,the shadow mask deposition was configured to allow certain regions ofthe silver surface to be exposed to a magnesium flux through a shadowmask aperture while masking other regions of the silver surface.Magnesium was deposited at a rate of about 2 Å/s.

FIG. 52A is a top view of a SEM image of the comparative sample. Anapproximate interface is shown using a dotted line in FIG. 52A. A firstregion 5203 corresponds to the masked region, and a second region 5201corresponds to the exposed region over which a magnesium coating wasdeposited.

FIG. 52B is a cross-sectional SEM image of the comparative sample. Ascan be seen in FIG. 52B, the magnesium coating deposited over the secondregion 5201 includes a relatively long (about 6 μm) tapering or tailportion 5214 where a thickness of the portion 5214 gradually tapers.

Example 7 (Comparative Example C)

To characterize an effect of deposition rate on a nucleation inhibitingproperty of a nucleation inhibiting coating including HT211, a series ofcomparative samples with varying layer thicknesses of HT211 werefabricated.

Specifically, the samples were fabricated by depositing about 10 nmlayer thickness of HT211 over an entire surface of a glass substrate,followed by open mask deposition of magnesium. Various evaporation rateswere used to deposit a magnesium coating; however in preparing eachsample, a deposition time was adjusted accordingly to obtain a referencelayer thickness of magnesium of either about 100 nm or about 1000 nm.

As used in this example, a reference layer thickness refers to a layerthickness of magnesium that is deposited on a reference surfaceexhibiting a high initial sticking coefficient (e.g., a surface with aninitial sticking coefficient of about or close to 1.0). For example, thereference surface may be a surface of a QCM positioned inside adeposition chamber for the purpose of monitoring a deposition rate andthe reference layer thickness. In other words, the reference layerthickness does not indicate an actual thickness of magnesium depositedon a target surface (e.g., a surface of the nucleation inhibitingcoating), but rather refers to the layer thickness of magnesium that isdeposited on the reference surface.

FIG. 53 shows a plot of transmittance versus wavelength for varioussamples fabricated using various deposition rates and associatedreference layer thicknesses. Based on the transmittance data, it can beseen that a sample with a relatively low magnesium reference layerthickness of about 100 nm, which was deposited at a low deposition rateof about 0.2 Å/s, exhibited the highest transmittance. However, when asample with substantially identical reference layer thickness wasdeposited at a higher deposition rate of about 2 Å/s, the transmittancewas lower across an entire measured spectrum. The lowest transmittancewas detected for a sample with a relatively high magnesium referencelayer thickness of about 1000 nm deposited using a relatively high rateof about 2 Å/s.

It is postulated that the reduced transmittance observed in the blueregion (about 400-475 nm) of the spectrum for all three samples may beattributed to absorption by magnesium oxide, which may be present in thesamples due to oxidation of the deposited magnesium.

Example 8

In order to characterize an effect of using various materials to form anucleation inhibiting coating, a series of samples were prepared usingdifferent materials to form the nucleation inhibiting coating.

The samples were fabricated by depositing about 10 nm layer thickness ofthe nucleation inhibiting coating on top of a glass substrate surface.The samples were then subjected to open mask deposition of magnesium.For each of the samples, magnesium was deposited at a rate of about 2Å/s until a reference layer thickness of about 1000 nm was reached.

FIG. 54 is a plot of transmittance versus wavelength for the samplesfabricated with various materials. As can be seen, the sample fabricatedwith TAZ exhibited the highest transmittance, followed by BAlq. Bothsamples fabricated with HT211 and Liq were found to exhibitsubstantially lower transmittance compared to those prepared with TAZand BAlq, due to a greater amount of magnesium being deposited onsurfaces of HT211 and Liq.

Example 9

A series of samples were prepared to assess an effect of providing anauxiliary electrode according to an example embodiment.

A first reference sample was prepared by depositing a layer of Mg:Ag ona substrate surface to replicate a typical common cathode used in atop-emission AMOLED display device.

A second reference sample was prepared by selectively depositing anauxiliary electrode in the form of a repeating grid on top of anon-conducting substrate surface. A pattern of the auxiliary electrodeis shown in FIG. 55. Specifically, the auxiliary electrode 5501 includesa plurality of apertures 5505 formed therein, such that if the auxiliaryelectrode 5501 is fabricated on an AMOLED device, each aperture 5505would substantially correspond to an emissive region (e.g., a pixel orsubpixel) of the device with the auxiliary electrode 5501 beingdeposited on a non-emissive region (e.g., an inter-pixel orinter-subpixel region). An average width or size of each aperture 5505was about 70 μm, and a width of each strip or segment of the auxiliaryelectrode 5501 was about 15-18 μm. The auxiliary electrode 5501 wasformed using substantially pure (about 99.99% purity) magnesium.

An evaluation sample was prepared by depositing an auxiliary electrode(under the conditions used for the second reference sample) on top ofthe Mg:Ag layer of the first reference sample. Specifically, anucleation inhibiting coating was selectively deposited on top of theMg:Ag layer using a shadow mask, and a resulting patterned surface wasthen exposed to magnesium vapor to selectively deposit the magnesiumauxiliary electrode to result in a similar pattern as shown in FIG. 55.

Sheet resistances of the samples were measured, and results of themeasurements are summarized in Table 7 below.

TABLE 7 Sheet resistance measurements First Reference Second ReferenceEvaluation Sample Sample Sample Sheet Resistance 22.3 0.13 0.1 (ohm/sq)

As shown in the table above, the first reference sample (Mg:Ag layer)was found to exhibit a relatively high sheet resistance of about 22.3Ω/sq. The second reference sample and the evaluation sample were foundto have substantially lower sheet resistances of about 0.13 Ω/sq andabout 0.1 Ω/sq, respectively. Accordingly, it was confirmed that, byproviding an auxiliary electrode according to the example embodiment inelectrical connection with a thin film conductor (e.g., a commoncathode), the sheet resistance of the thin film conductor may besubstantially reduced.

As used herein, the terms “substantially,” “substantial,”“approximately,” and “about” are used to denote and account for smallvariations. When used in conjunction with an event or circumstance, theterms can refer to instances in which the event or circumstance occursprecisely, as well as instances in which the event or circumstanceoccurs to a close approximation. For example, when used in conjunctionwith a numerical value, the terms can refer to a range of variation ofless than or equal to ±10% of that numerical value, such as less than orequal to ±5%, less than or equal to ±4%, less than or equal to ±3%, lessthan or equal to ±2%, less than or equal to ±1%, less than or equal to±0.5%, less than or equal to ±0.1%, or less than or equal to ±0.05%.

In the description of some embodiments, a component provided “on” or“over” another component, or “covering” or which “covers” anothercomponent, can encompass cases where the former component is directly on(e.g., in physical contact with) the latter component, as well as caseswhere one or more intervening components are located between the formercomponent and the latter component.

Additionally, amounts, ratios, and other numerical values are sometimespresented herein in a range format. It can be understood that such rangeformats are used for convenience and brevity, and should be understoodflexibly to include not only numerical values explicitly specified aslimits of a range, but also all individual numerical values orsub-ranges encompassed within that range as if each numerical value andsub-range is explicitly specified.

Although the present disclosure has been described with reference tocertain specific embodiments, various modifications thereof will beapparent to those skilled in the art. Any examples provided herein areincluded solely for the purpose of illustrating certain aspects of thedisclosure and are not intended to limit the disclosure in any way. Anydrawings provided herein are solely for the purpose of illustratingcertain aspects of the disclosure and may not be drawn to scale and donot limit the disclosure in any way. The scope of the claims appendedhereto should not be limited by the specific embodiments set forth inthe above description, but should be given their full scope consistentwith the present disclosure as a whole. The disclosures of all documentsrecited herein are incorporated herein by reference in their entirety.

1. An opto-electronic device comprising: a substrate; a nucleation inhibiting coating covering a first region of the substrate; and a conductive coating including a first portion and a second portion, the first portion of the conductive coating covering a second region of the substrate, and the second portion of the conductive coating partially overlapping the nucleation inhibiting coating, wherein the second portion of the conductive coating is spaced from the nucleation inhibiting coating by a gap, and wherein the conductive coating further includes a third portion in contact with the nucleation inhibiting coating, and the third portion of the conductive coating includes disconnected clusters on a surface of the nucleation inhibiting coating.
 2. The opto-electronic device of claim 1, wherein the second portion of the conductive coating extends over an overlapping portion of the nucleation inhibiting coating, and is spaced from the overlapping portion of the nucleation inhibiting coating by the gap.
 3. The opto-electronic device of claim 2, wherein another portion of the nucleation inhibiting coating is exposed from the conductive coating.
 4. The opto-electronic device of claim 1, wherein and a thickness of the third portion of the conductive coating is no greater than 5% of a thickness of the first portion of the conductive coating.
 5. The opto-electronic device of claim 4, wherein the second portion of the conductive coating extends over the third portion of the conductive coating, and is spaced from the third portion of the conductive coating.
 6. The opto-electronic device of claim 1, wherein the conductive coating further includes an intermediate portion disposed between the first portion of the conductive coating and the second portion of the conductive coating, and the intermediate portion of the conductive coating is in contact with the nucleation inhibiting coating.
 7. The opto-electronic device of claim 1, wherein the nucleation inhibiting coating includes a polymer.
 8. The opto-electronic device of claim 7, wherein the polymer is selected from the group consisting of: fluoropolymer, polyvinyl biphenyl, and polyvinylcarbazole.
 9. The opto-electronic device of claim 7, wherein the polymer is a fluoropolymer.
 10. The opto-electronic device of claim 9, wherein the fluoropolymer is selected from a group consisting of: perfluorinated polymer and polytetrafluoroethylene.
 11. The opto-electronic device of claim 1, wherein the nucleation inhibiting coating includes a polycyclic aromatic compound.
 12. The opto-electronic device of claim 1, wherein the nucleation inhibiting coating includes an organic compound including a core moiety and a terminal moiety bonded to the core moiety, and the terminal moiety includes a biphenylyl moiety, a phenyl moiety, a fluorene moiety, or a phenylene moiety.
 13. The opto-electronic device of claim 12, wherein the core moiety includes a cyclic hydrocarbon moiety.
 14. The opto-electronic device of claim 1, wherein the conductive coating includes magnesium.
 15. The opto-electronic device of claim 1, wherein the nucleation inhibiting coating is characterized as having an initial sticking probability for a material of the conductive coating of no greater than 0.02.
 16. The opto-electronic device of claim 1, wherein the substrate includes a backplane and a frontplane disposed on the backplane.
 17. The opto-electronic device of claim 16, wherein the backplane includes a transistor, and the frontplane includes an electrode electrically connected to the transistor, and at least one organic layer disposed on the electrode.
 18. The opto-electronic device of claim 17, wherein the electrode is a first electrode, and the frontplane further includes a second electrode disposed on the organic layer.
 19. The opto-electronic device of claim 18, wherein the conductive coating forms the second electrode.
 20. The opto-electronic device of claim 1, wherein the opto-electronic device is an organic light emitting diode (OLED) device, and the OLED device includes a light transmissive portion configured to transmit light therethrough.
 21. The opto-electronic device of claim 20, wherein the nucleation inhibiting coating is deposited in the light transmissive portion.
 22. An opto-electronic device comprising: a substrate; a nucleation inhibiting coating covering a first region of the substrate; and a conductive coating covering a laterally adjacent, second region of the substrate, wherein the conductive coating includes an electrically conductive material, and the nucleation inhibiting coating is characterized as having an initial sticking probability for the electrically conductive material of no greater than 0.02, and wherein the conductive coating further includes a portion in contact with the nucleation inhibiting coating, and the portion of the conductive coating includes disconnected clusters on a surface of the nucleation inhibiting coating.
 23. The opto-electronic device of claim 22, wherein the nucleation inhibiting coating includes a polymer.
 24. The opto-electronic device of claim 23, wherein the polymer is selected from the group consisting of: fluoropolymer, polyvinyl biphenyl, and polyvinylcarbazole.
 25. The opto-electronic device of claim 23, wherein the polymer is a fluoropolymer.
 26. The opto-electronic device of claim 25, wherein the fluoropolymer is selected from a group consisting of: perfluorinated polymer and polytetrafluoroethylene.
 27. The opto-electronic device of claim 22, wherein the electrically conductive material includes magnesium.
 28. The opto-electronic device of claim 22, wherein the opto-electronic device is an organic light emitting diode (OLED) device, and the OLED device includes a light transmissive portion configured to transmit light therethrough.
 29. The opto-electronic device of claim 28, wherein the nucleation inhibiting coating is provided in the light transmissive portion.
 30. The opto-electronic device of claim 28, wherein the conductive coating is an electrode of the OLED device. 